When CISA issues an emergency directive, the message to every federal agency and every security team paying attention is to patch now. For CVE-2026-50751, a CVSS 9.3 authentication bypass in Check Point Remote Access VPN, that directive landed on June 21. despite exploitation beginning in early May. That, six-week active intrusion gap is not a footnote. It is the entire story.

The flaw itself is straightforward in the worst possible way. A logic error in the certificate-validation process, triggered when the deprecated IKEv1 key-exchange protocol is enabled, allows a remote attacker to establish a fully authenticated VPN session without a valid password. No phishing. No credential theft. No lateral movement required to reach the perimeter. The attacker walks through the front door, and the door logs it as a legitimate entry.

By the time Check Point disclosed the vulnerability on June 8, a Qilin ransomware affiliate had already used it to compromise a few dozen organizations worldwide. The post-access playbook was efficient, including Rclone for data exfiltration, the Tox protocol for command-and-control communication routed through disposable VPS infrastructure. Quiet, fast, and designed to complete the job before detection had a chance to matter.

The security product became the attack vector

There is a particular irony to CVE-2026-50751 that the industry needs to sit with. The device that was breached is not an unpatched workstation or a misconfigured cloud bucket. It is the VPN gateway, the product sold specifically to keep attackers outside the perimeter. The control designed to prevent unauthorized access became the mechanism of it.

This is not unique to Check Point, and it is not a criticism of any single vendor. It reflects a structural problem with perimeter-dependent security architecture. When the perimeter device is the trust anchor, compromising that device does not just breach the perimeter. It inherits the perimeter’s authority. Every downstream control, every identity verification, every behavior-based detection tool is now reasoning about a session it believes is legitimate, because the VPN said so.

That is the condition Qilin exploited. And patching the vulnerability, while absolutely necessary, does nothing to change the position of organizations that were breached during the May-June window. For them, the attacker is already operating as a trusted user. The CISA directive is not a remedy for those organizations. It is a message to everyone else.

Why the standard response falls short

The standard sequence after a disclosure like this is one we’ve all heard before—patch the affected systems, update detection signatures, review logs for indicators of compromise. While each of these steps is good practice, none of them solves the underlying problem.

Patching closes the door for future attackers, but it does not evict the ones already inside. Detection signatures help identify known post-exploitation behavior, but ransomware affiliates have demonstrated consistent operational discipline, using legitimate tools for exfiltration and standard protocols for command-and-control precisely because these approaches blend into normal traffic. Log review is valuable, but the attackers who exploited the vulnerability had weeks of access before anyone was looking.

The detect-and-respond model assumes that detection arrives before the damage is complete. Against a weaponized zero-day with a six-week head start, that assumption does not hold. By the time an alert fires, the data has moved. The ransomware is staged. The ransom clock has started.

Making the endpoint harder to exploit

The Check Point vulnerability forces a critical question: how do you stop payload execution when an attacker has already succeeded at authentication and bypassed every other defense?

It requires moving the defensive layer to the endpoint itself, at the point of execution, where the ransomware payload has to operate regardless of how access was obtained. Techniques that morph the runtime memory environment, transforming the structures that malware needs to find and use at execution time, stop the payload deterministically. The attacker can have authenticated credentials, a legitimate session, and weeks of undetected access. If the target environment does not look like what the payload expects, the payload fails.

This is not a replacement for patching. Organizations should apply the Check Point fix immediately, and they should treat any system with IKEv1 enabled during the May-June window as potentially compromised. But patching is the beginning, as the organizations that were inside the six-week exploitation window need a control that works after the perimeter is gone.

The lesson before the next directive

CISA will issue another emergency directive. There will be another authentication bypass, another perimeter device turned attack vector, another financially motivated threat actor with a head start measured in weeks. The patch-and-detect cycle will play out again, and organizations that had their exposure managed entirely at the perimeter will find themselves in the same position.

The lesson here is not that Check Point failed or that VPNs are over. It is that any architecture where a single authentication bypass gives an attacker operating authority over the entire environment has a structural problem that no patch resolves. Closing the door is necessary. Making sure the ransomware cannot detonate even after the attacker is inside is the part the industry still has not solved at scale.

That is the conversation the CISA directive should be starting, and mostly is not.

The post Why patch directives only go so far appeared first on CyberScoop.

Two men pleaded guilty in the United Kingdom this week to criminal charges stemming from an August 2024 cyberattack that crippled Transport for London, the entity responsible for the public transport network in the Greater London area. The duo were key members of a prolific cybercrime group known as Scattered Spider, and their guilty pleas came on the first day of what was expected to be a six-week trial.

Owen Flowers (left) 18, and Thalha Jubair, 20. Image: UK National Crime Agency (NCA).

Thalha Jubair, 20, of East London and 18-year-old Owen Flowers of Walsall admitted conspiring to commit unauthorized acts against Transport for London computer systems and causing risk of serious damage to human welfare. According to a report from the BBC, Flowers alone admitted to being part of a conspiracy to hack into U.S. based healthcare providers SSM Health Care Corporation and Sutter Health in September 2024.

Jubair is also wanted by U.S. law enforcement agencies. In September 2025, prosecutors in New Jersey unsealed an indictment alleging Jubair and other Scattered Spider members committed computer fraud, wire fraud, and money laundering in relation to 120 computer network intrusions involving 47 U.S. entities between May 2022 and September 2025, and that the group’s victims paid at least $115 million in ransom payments.

In July 2025, KrebsOnSecurity reported that Flowers and Jubair were arrested in the United Kingdom in connection with Scattered Spider ransom attacks against the retailers Marks & Spencer and Harrods, and the British food retailer Co-op Group. Multiple sources familiar with those investigations said Flowers was the Scattered Spider member who anonymously gave interviews to the media in the days after the group’s September 2023 ransomware attacks disrupted operations at Las Vegas casinos operated by MGM Resorts and Caesars Entertainment.

According to prosecutors, Jubair co-ran a bustling Telegram channel called Star Chat, the home of a SIM-swapping group that used voice- and SMS-based phishing attacks to steal credentials from employees at the major wireless providers in the U.S. and U.K. The group would then use that access to sell a service that could redirect a target’s phone number to a device the attackers controlled and intercept the victim’s calls and text messages (including one-time codes for multi-factor authentication).

A receipt from Star Fraud Chat’s SIM-swapping service targeting a T-Mobile customer after the group gained access to internal T-Mobile employee tools. “Rocket Ace” was one of Jubair’s hacker handles, according to U.S. prosecutors.

New Jersey prosecutors also allege Jubair also was involved in a mass SMS phishing campaign during the summer of 2022 that stole single sign-on credentials from employees at hundreds of companies. That weeks-long SMS phishing campaign led to intrusions and data thefts at more than 130 organizations, including LastPass, DoorDash, Mailchimp, Plex and Signal.

KrebsOnSecurity reported last year that one of Jubair’s alter egos at age 15 was “Everlynn,” a hacker who sold fraudulent “emergency data requests” that used compromised police and government email addresses to demand subscriber data (e.g. username, IP/email address) from major tech companies, claiming the requests concerned urgent matters of life and death and could not wait for a court order.

In April 2026, 24-year-old British national and Scattered Spider member Tyler “Tylerb” Buchanan pleaded guilty to wire fraud conspiracy and aggravated identity theft for participating in the group’s SMS phishing spree in the summer of 2022. The government said Buchanan, Jubair and others used the credentials harvested in that phishing campaign to steal at least $8 million in cryptocurrency from victims throughout the United States. Buchanan is currently scheduled to be sentenced on October 2.

In August 2025, 20-year-old Scattered Spider member from Florida named Noah Michael Urban was sentenced to 10 years in federal prison and ordered to pay $13 million in restitution, after pleading guilty to charges of wire fraud and conspiracy.

The U.S. Department of Justice says three alleged Scattered Spider defendants indicted along with Buchanan still face charges, including Ahmed Hossam Eldin Elbadawy, 24, a.k.a. “AD,” of College Station, Texas; Evans Onyeaka Osiebo, 21, of Dallas, Texas; and Joel Martin Evans, 26, a.k.a. “joeleoli,” of Jacksonville, North Carolina.

Flowers and Jubair are slated to be sentenced in a London court on July 15, 2026.

Authorities on Thursday disrupted a botnet, a malware framework and seized infrastructure that Evil Corp and other cybercrime groups used to steal data and break into various networks.

The globally coordinated effort targeted SocGholish, multi-stage malware that has compromised websites, redirected users to traffic distribution systems (TDS) and slipped malware into their networks since 2017.

“The malware establishes an initial foothold into victim computers, collectively known as a botnet, and is then used by threat actors for further targeting with ransomware campaigns and espionage,” the FBI’s cyber division said in a statement. 

Cybersecurity firms, researchers and officials from the United States, Canada, Germany, the Netherlands and Europol took down 106 servers and remediated nearly 15,000 sites that were infected with the malware. Officials also disabled the botnet and notified victims.

Sites infected with SocGholish, which are primarily hosted on WordPress, were widespread and provided everyday services including restaurants and auto repair shops, according to the Dutch National Police. 

The botnet, also known as “FakeUpdates,” is linked to the Russian cybercrime group Evil Corp. It also provided initial access to other ransomware variants, including DoppelPaymer, WastedLoocker, Hades Ransomware, LockBit, RansomHub and others, according to Infoblox, which participated in the takedown. 

Proofpoint, which also participated in the disruption, described Evil Corp as one of the most prominent cybercrime groups in operation and the “grandfather” of a threat type that compromises websites and uses TDS to redirect users to malware.

Following the takedown, the FBI issued a public service announcement warning about cybercriminals using TDS to break into victim networks for ransomware or other financial scams. 

Cybercriminals redirect traffic from sites to bypass firewalls, obscure their activity, identify potential victims and send them to phishing pages to steal credentials, initiate financial scams, access networks, deliver other malware, and sell access to other cybercriminals, officials said.

The law enforcement action was part of Operation Endgame, a multinational effort targeting cybercrime since 2024, and more narrowly for the FBI part of Operation Riptide, an ongoing campaign targeting cybercriminals and the infrastructure and financial networks they use to commit fraud.

The post Authorities disrupt Evil Corp’s SocGholish botnet appeared first on CyberScoop.

TeamPCP is on a rampage through open-source software.

In less than four months, the threat actor has compromised and injected malicious code into more than 1,000 software packages. The extraordinary spree has transformed how software developers and maintainers distribute and manage their code, as their dependencies and repositories have become one of the most effective and prevalent attack vectors this year.

While there has been a host of technical exploits, TeamPCP’s greatest attack has been the uprooting of trust — repeatedly proving that most organizations fail to verify the code they ingest into their systems is legitimate, abusing a nearly blind faith that much of the software development industry relies on to power today’s modern economy.

Starting with Trivy in February, TeamPCP’s attacks have shaken that trust many times over.

The scale of TeamPCP’s attacks lies partly in the automated systems companies use to deploy code, like CI/CD pipelines. It is also capitalizing on new security gaps created by developers’ increasing reliance on AI. Yet, with relatively low effort and unoriginal tactics, TeamPCP is wrecking open-source frameworks and underlying systems at levels the technology community has rarely reckoned with.

“Developers didn’t do a great job of analyzing the security of their open-source dependencies before but, now with AI, there’s in some cases virtually no human in the loop or any kind of sanity check on what these tools are doing,” Feross Aboukhadijeh, founder and CEO at Socket, told CyberScoop.

“You have agents installing packages that haven’t been vetted,” he said. “When an attacker gets in, the impact is even broader because there’s less checks and balances to stop it from affecting everybody.”

TeamPCP hasn’t identified a new problem or proved anything novel. The crux of these attacks hinge on a central theme — defensive vulnerabilities the entire software industry has known about for years. Researchers and developers know the open source trust model is broken and susceptible to sabotage. Yet, the software industry has not fixed this problem. 

“The speed and scale of these attacks is what makes it most notable, not necessarily the methodology behind it, because at the core it is really about exploiting third-party trusts that we have,” said Kimberly Goody, senior manager at Google Threat Intelligence Group.

Software packages are typically subjected to intensive security monitoring to test for vulnerabilities and poisoned updates before they are released to live environments. 

Yet, the real vulnerability highlighted by TeamPCP lies further up the chain of command with the organizations or individuals that publish these packages to the wider market, according to Nathaniel Quist, manager of cloud threat intelligence at Palo Alto Networks.

“It is their responsibility to secure their credentials and not provide a jump off point to trigger a supply-chain event,” he said. “Everything that interacts with or crosses through that zone must be highly monitored and controlled to ensure a compromise can be contained quickly and easily.”

TeamPCP’s motivation

TeamPCP, like any prolific cybercriminal, has captured significant attention from threat hunters since it emerged in late 2025. Google attributes the activity to one core operator.

The company said it traced TeamPCP’s residential and mobile IP address connections to South Africa, indicating the primary operator was located there during at least some of its attacks.

“We don’t believe that there’s an established core group, at least not yet, and that a lot of this has been conducted by an individual,” Goody said. Google declined to name the core operator or confirm it knows the person’s true identity. 

Palo Alto Networks said the core manager of TeamPCP uses the “ResoluteXBF” handle on multiple platforms. The cybersecurity firm is also tracking two additional core members: “diencracked” and “Shinigami.”

If TeamPCP is primarily run by one person, law enforcement has a rare opportunity to make a lasting impact with a single arrest.

TeamPCP has collaborated with other cybercriminals, but most of those partnerships were short-lived and ended in a public feud or otherwise failed to get off the ground in any meaningful way, Goody said.

Researchers have linked TeamPCP to extortion crews, dark web forums and affiliates including Lapsus$, ShinyHunters, Vect, DragonForce, BreachForums and “HasanBroker.” TeamPCP listed about 4,000 private code repositories on a dark web forum with an asking price of $95,000.

The actions to date, including unpredictable behavior, indicate motivations beyond financial gain and a “clear desire for notoriety,” Goody said. “They seem to like to make chaos.”

Quist draws the same conclusion from his months-long investigation, noting that it encourages other cybercriminals to get in on the action, at one point offering financial rewards for the largest software supply-chain attack. 

TeamPCP isn’t in the game for extortion payments, he said. “These actors are more interested in the underground street cred they are gaining” and “causing as much damage and mayhem as possible.”

Victims abound, but exposure limited

TeamPCP has been remarkably noisy, opportunistically injecting malware into open-source software for the purpose of stealing credentials for Kubernetes environments, Amazon Web Services, Microsoft Azure, Google Cloud and many other connected services.

The group’s claimed victim list is staggering: Checkmarx, Bitwarden, LiteLLM, Telnyx, Mercor AI, PyTorch Lightning, AntV, SAP, GitHub, TanStack, UiPath, MistralAI, Microsoft DurableTask, Red Hat and Nx Console.

The full collection of packages compromised or poisoned by TeamPCP to date accounts for roughly 500 million weekly downloads combined, according to Quist.

While the breadth of potential downstream compromise flowing from those downloads is substantial, many endpoints infected with those malware-riddled packages aren’t exposed to the internet and less susceptible to attack, he added.

“I don’t think there’s going to be a very extremely large number of victims,” Quist said. “There’s going to be a lot of people who potentially could be compromised and have potentially vulnerable packages in their environment, but that doesn’t necessarily mean they’re in an exploitable position.”

While these incidents have grabbed headlines, TeamPCP hasn’t accumulated payouts nearly as large as other cybercriminals. The broader reputational impact it has wrought, however, is massive.

TeamPCP has publicly claimed more than 10,000 victims and about $90,000 in extortions, according to Quist.

“They might not be making a lot of money, but they are causing a lot of impact,” Goody said. “Their campaigns have been very disruptive.”

How TeamPCP’s operating model targets development

TeamPCP’s victim list has grown as its hijacked open-source repositories on npm, PyPI, GitHub and other outsourced developer tools that are incorporated into upstream code running in production environments.

Developer laptops and other endpoints that are assigned to install, build and publish software widely contain keys and access to source code that create incredibly valuable supply-chain targets for attackers, Amitai Cohen, head of the attack vector intel team at Wiz, explained during a June presentation on TeamPCP at SleuthCon in Arlington, Va. 

The group targets CI runners, which are automated systems that build, test, and publish code. TeamPCP injects malware into the code repositories these runners maintain. When other developers pull that code into their own systems, they unknowingly download the malware alongside it. 

Some of these artifacts, including Python libraries, npm registries and GitHub Actions, are downloaded almost immediately by thousands or millions of developers who’ve set their runners up to consistently pull the latest version, according to Cohen. “We as a security industry have taught them that that is the right thing to do. You want to use the latest version because you want to be protected against vulnerabilities, and obviously you want to benefit from all the latest features.”

That instinct is exactly what TeamPCP exploits. By compromising one company’s CI/CD workflow, the group gains access to every downstream user who automatically pulls that infected code. “This is what allows [TeamPCP] to leverage initial access to some patient zero, some company that had a vulnerability in their CI/CD workflow, in order to gain access to their downstream users,” Cohen said. “That’s just how the software supply chain works. Everything has dependencies upon dependencies upon dependencies.”

Some of the packages compromised by TeamPCP were live for almost 13 hours, but security practitioners have responded by identifying code-injection attacks much quicker now, pulling some compromised repositories within 15 minutes, said Ben Read, director of strategic intelligence at Wiz.

The threat group’s operations remain high-tempo. TeamPCP infects new software packages almost daily, validates compromises and captures sensitive data within 24 hours, according to Wiz researchers.

The threat group has consistently evolved its tactics, developing payloads in JavaScript and Python while spreading from local files to Kubernetes application programming interfaces and bundled software development kits. Most recently, it’s been stealing credentials via custom protocols. 

The group’s ambitions have expanded beyond its own attacks. TeamPCP is also responsible for a self-replicating piece of malware known as Mini Shai-Hulud, which infected hundreds of software packages across open-source registries in back-to-back attack sprees last month. A TeamPCP affiliate published the full source code for the malware on GitHub last month and encouraged other cybercriminals to use it for their own campaigns.

“TeamPCP is going for volume. They are not being discriminating, they’re not necessarily trying to be stealthy or trying to maximize ROI. They’re going for an all-of-the-above strategy,” Read said during the Sleuthcon presentation.

Defensive gaps create openings for attack

TeamPCP’s attack spree has also underscored how difficult it is for organizations to revoke compromised secrets. Multiple victims have experienced recurring infections, sometimes falling prey to TeamPCP three times within a month, because they didn’t rotate secrets properly, Cohen said. 

At its core, these attacks highlight a direct trade-off organizations accept when they update software quickly to fix vulnerabilities, but learn that doing so too quickly could expose them to illegitimate registries containing malware.

TeamPCP has targeted what Aboukhadijeh describes as a “public good,” open-source registries that were never perfect but widely trusted and rarely turned into a point of entry for supply-chain attacks. 

Rapid open source software installation is one of the most dangerous things an organization can do right now, he said, adding that there’s a roughly 1 in 10 chance that any package installed by an organization could trigger an active attack. 

TeamPCP has compromised security scanners, password managers, automation tools, data visualization software, and CI/CD infrastructure across various environments.

And it’s lifted a trove of credentials and other sensitive data from victims.

Researchers like Cohen at Wiz, who have been tracking this attack spree since the beginning, are nearing a breaking point. 

“This is also too hard on us. We’re very tired. I’m sure a lot of people working on this problem space are very tired, and it’s just kind of become untenable,” Cohen said.

“You can’t keep existing in a world where you wake up every morning and some super prevalent package is compromised and everybody’s just going to be using it like nothing,” he added. “We need to start taking this a bit more seriously.”

The post How software development’s speed obsession enabled TeamPCP’s chaos crusade appeared first on CyberScoop.

The attackers deployed a new Go-based backdoor that uses Microsoft Teams servers for command-and-control.

The post Microsoft Teams Relay Servers Abused in DragonForce Ransomware Attack appeared first on SecurityWeek.

Mackay Sugar was targeted in a cyberattack carried out by a threat group known as The Gentlemen.

The post Ransomware Attack Shuts Down Mills of Australia’s Second-Largest Sugar Producer appeared first on SecurityWeek.

Oleksii Oleksiyovych Lytvynenko admitted to working on the development of a loader for the Conti gang.

The post Ukrainian Man Pleads Guilty in US to Conti Ransomware Charges appeared first on SecurityWeek.

A longtime former member of Conti, a ransomware group that attacked more than 1,000 organizations globally before it disbanded in 2022, pleaded guilty to participating in some of those attacks in federal court Wednesday, the Justice Department said.

Oleksii Oleksiyovych Lytvynenko, also known as Alexsey Alexseevich Litvinenko, admitted he joined the prolific cybercrime group in September 2021 and held data on 12 victims, including eight based in the United States. The 44-year-old told the court he developed malware that Conti used in some of its attacks, according to officials. 

“The defendant and his conspirators used the Conti ransomware to terrorize people and businesses in the United States and around the world, causing millions of dollars in damage,” A. Tysen Duva, assistant attorney general of the Justice Department’s criminal division, said in a statement.

Lytvynenko and his co-conspirators used the ransomware to attack more than 1,000 victims globally, ensnaring victims in 47 states, Washington, Puerto Rico and about 31 countries, according to the Justice Department. The FBI estimates Conti extorted more than $150 million in ransom payments from victims.

The Ukrainian national pleaded guilty to conspiracy to commit wire fraud and faces up to 20 years in prison upon sentencing, which is scheduled for Sept. 10. 

Lytvynenko was arrested in Ireland in July 2023, extradited to the United States in October 2025, and remains in federal custody in Tennessee where at least three of his victims are based. He left Ukraine in 2022 and obtained temporary protective status in Ireland, residing in Cork at the time of his arrest. 

Prosecutors said Lytvynenko and his co-conspirators extorted about $634,000 in Bitcoin from two victims in Tennessee, including an undisclosed government entity that resulted in the compromise of a sheriff’s department, local emergency medical services and a local police department. According to an indictment that was unsealed last fall, Lytvynenko and his co-conspirators also leaked data they stole from another Tennessee-based victim after it refused to pay a $3 million ransom demand.

Four of Lytvynenko’s alleged co-conspirators — Maksim Galochkin, Maksim Rudenskiy, Mikhail Mikhailovich Tsarev and Andrey Yuryevich Zhuykov — were indicted in 2023 in the same federal court for crimes related to their suspected involvement in Conti attacks from 2020 to 2022. 

Authorities said Lytvynenko engaged in cybercrime after Conti disbanded and its members splintered off into new groups, adding that he “was asleep but within arms’ reach of an open laptop running Cobalt Strike” at the time of his arrest.

At one point, Conti was among the most prolific ransomware groups globally, impacting hundreds of critical infrastructure providers, Costa Rica’s government in 2022, and ultimately leading the State Department to offer a $10 million reward for information related to Conti’s leaders. The group was notoriously resilient, bouncing back with new infrastructure and hitting new targets after a massive leak exposed chats between the group’s members in 2022.

Conti disbanded later that year, but members of the Cyrillic-language group rebranded under three subgroups: Zeon, Black Basta and Quantum, which quickly rebranded to Royal, before rebranding again to BlackSuit in 2024.

“Lytvynenko’s guilty plea is a significant step toward holding cyber criminals accountable for the damage they inflict on victims worldwide,” Brett Leatherman, assistant director of the FBI’s cyber division, said in a statement “Lytvynenko profited from fear and coercion, conspiring to use Conti ransomware to extort victims and steal their data.”

The post Conti ransomware group member pleads guilty, faces up to 20 years in prison appeared first on CyberScoop.

A cybercrime group known as The Gentlemen has emerged as the second most active ransomware gang by victim count, rapidly attracting a talented pool of hackers through an aggressive recruitment strategy that promises affiliates 90 percent of any ransom paid by victims. This post examines clues pointing to a real life identity for the administrator of The Gentlemen ransomware group.

A graphic created and shared by The Gentlemen ransomware group administrator Hastalamuerte on Breachforums in May 2026. Credit: ke-la.com.

Experts at the security firm Check Point Software have been closely covering exploits of The Gentlemen, a so-called “ransomware-as-a-service” (RaaS) offering that pays affiliates handsomely to help spread the group’s malware.

“A 90/10 affiliate revenue split — compared to the industry standard 80/20 — is accelerating the group’s growth by attracting experienced operators from competing programs,” the researchers wrote in April.

Check Point found The Gentlemen are the second most active ransomware group by victim count so far this year, claiming at least 332 published victims since the group’s inception in mid-2025 and more than 240 in 2026 alone.

According to Check Point, the group targets Internet-facing devices (VPNs, firewalls) as their entry point, and once inside moves quickly to encrypt entire networks within hours.

Check Point says the administrator and primary operator of the ransomware group uses the nickname Zeta88 on the Russian-language cybercrime forums, and that this individual was previously known under the moniker Hastalamuerte. Check Point noted that a breach of the group’s backend infrastructure made it clear that Hastalamuerte/Zeta88 is the person who assembles the locker and RaaS panel, manages payments, and is essentially the administrator of the entire program who receives 10 percent of all ransoms.

WHO IS HASTALAMUERTE?

The cyber intelligence firm Intel 471 shows that the user Hastalamuerte is a Russian and English speaking person who registered on almost a dozen cybercrime forums between 2019 and the present day, including Exploit, Breachforums, Ramp_V2, BHF, Raidforums, and Nulled.

Intel 471 reveals that Hastalamuerte registered on Breachforums in January 2025 from an Internet address in Izhevsk, the capital city of Russia’s Udmurt Republic. Likewise, the user Zeta88 signed up at the English-language cybercrime forum Breached in August 2022 from a different Internet address in Izhevsk.

Intel 471 finds Hastalamuerte registered on Raidforums in 2020 using the email address hastalamuerte1488@protonmail.com (1488 is a common combination of two numeric symbols associated with white supremacy). A lookup on this address at the open source intelligence service Epieos shows it is connected to an account at Apple and to a phone number ending in 04.

Epieos says that Protonmail address is also linked to a GitHub account under the username SantaMuerte. That account is marked private, but a history of this user’s activity shows they are watching and developing a number of malware tools and exploits.

In April 2020, Hastalamuerte said on the crime forum Nulled that they could be contacted at the Telegram instant messenger name @hastalamuerte18, and the threat intelligence company Flashpoint finds this username is assigned the unique Telegram ID number 30907522 [full disclosure: Flashpoint is an advertiser on this blog].

The breach tracking service Constella Intelligence reports that Hastalamuerte’s Telegram ID is connected to another username — “bu4vs” — and to the Russian phone number 79127650004. Pivoting on this phone number in Constella fetches multiple records from hacked Russian government databases showing it is assigned to one Alexander Andreevich Yapaev, a 36-year-old from Izhevsk.

Constella reveals that phone number was used to create an account at the Russian social media platform Pikabu under the name “4apai18,” and shows Mr. Yapaev has signed up at a number of websites using the common surname Ivanov, or else “Chapaev” (the numeral 4 is often used as shorthand for a “ch” sound in Russian).

A search in Intel 471 for cybercrime forum members with the nickname SantaMuerte unearths an account by the same name created in 2020 on the Russian hacking forum Codeby. Intel 471 shows this user originally registered on Codeby with the not-so-subtle nickname Alexandr 4apaev.

Constella finds Mr. Yapaev regularly used the email address bu4vs@mail.ru. Meanwhile, Epieos shows this address is connected to a LinkedIn account for Alexander Yapaev, who lists himself as the head of B2B marketing at the company Uralenergo Udmurtia, one of Russia’s largest suppliers of electrotechnical and lighting products.

Mr. Yapaev did not respond to multiple requests for comment.

Nearly every time we publish one of these Breadcrumbs stories, readers are curious to know why it seems like so many cybercriminals from Russia apparently do little to hide their real life identities. The truth is that — Russian or not — most didn’t exactly set out to be arch criminals, but instead got drawn into the scene gradually over several years as their skills broadened and sharpened.

Another important dynamic is that the Russian government generally either co-opts or ignores cybercriminal activity within its borders so long as the hackers do not steal from or attack Russian businesses and citizens. As a result, successful cybercriminals in Russia are usually insulated from prosecution and arrest by foreign law enforcement agencies provided they occasionally pay off the right people and do not travel abroad. And cybercriminals who intend to strictly adhere to those unwritten rules may (at least initially) be less concerned about covering their tracks online.

But the simplest explanation is that cybercriminals of all nationalities tend to make a number of basic operational security mistakes early in their careers, when they are less savvy and have far less to lose by their carelessness. A review of Hastalamuerte’s early posts on the crime forums (circa 2019-2020) shows a relatively unsophisticated and low-skilled hacker still trying to learn the ropes and earn a positive reputation on these communities.

For example, in June 2020 Hastalamuerte’s Telegram account joined a multi-month training program (@pntst) to learn how to use popular penetration testing tools, and their candid posts to this hacker training camp show Hastalamuerte struggling to use these tools effectively. A Google-translated record of Hastalmuerte’s posts to @pntst is here.

Update, June 11, 10:23 a.m. ET:  The threat research group PRODAFT has released a detailed writeup on the history and current operations of The Gentlemen. PRODAFT said its findings match the same persona with “high confidence,” and found the administrator (Zeta88/Hastalamuerte) supplies affiliates with initial access directly, primarily Fortinet SSL-VPN credentials obtained through brute-force attacks or sourced from the group’s own leak database. They also discovered the administrator is using AI to develop and maintain the ransomware and associated tooling, as well as to assist with post-exploitation activity.

Focusing on hacking law firms in the US, the ransomware group relies on fast flux to hide its C&C infrastructure.

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Ransomware that combines robust encryption with rapid lateral movement significantly increases the risk and impact of an attack. The Gentlemen ransomware is a ransomware-as-a-service (RaaS) threat that is distinguished by its ability to pair its strong per-file encryption with an aggressive self-propagation capability designed to enable broad network compromise. In addition to using per-file ephemeral Curve25519 keys with XChaCha20 stream cipher, The Gentlemen ransomware attempts to spread across an environment using series of simultaneous, distinct lateral movement methods, increasing the likelihood of widespread impact once initial access is achieved.

Microsoft Threat Intelligence tracks the operators behind the ransomware as Storm-2697, a financially motivated threat actor that manages the RaaS platform known as “The Gentlemen” while affiliates carry out attacks. Emerging around mid-2025, The Gentlemen initially started as a closed ransomware group then began offering its RaaS to affiliates in September 2025. More recently, The Gentlemen operators established an official partnership with BreachForums, a popular cybercriminal marketplace, to recruit affiliates including penetration testers and initial access brokers. Given that The Gentlemen is already a widely adopted RaaS platform, this partnership may lead to increased activity as the program becomes accessible to a broader pool of threat actors.

The operators behind the ransomware use double extortion tactics, encrypting data while also exfiltrating sensitive information to pressure victims through the threat of public release if the ransom is not paid. The ransomware is written in Go and obfuscated with Garble to target the Windows environment. Microsoft has observed The Gentlemen ransomware impacting organizations across education, transportation, healthcare, and financial industries in North America, South America, Europe, Africa, and Asia.

In this blog, we present a detailed analysis of the Gentlemen ransomware encryptor, including its execution flow, defense evasion behaviors, encryption design, and lateral movement techniques. This research is intended to provide defenders, incident responders, and the broader security community with a better understanding of how the threat operates, from initial argument parsing and defense evasion, through its file encryption internals, to the full lateral movement that enables it to propagate across the network. We also provide mitigation guidance, Microsoft Defender detections, hunting queries, and indicators of compromise (IOCs) to help organizations defend against this threat and similar ransomware activity.

Pre-encryption

Command-line argument processing

The ransomware operator can control The Gentlemen encryptor through command-line arguments. A password is required for execution, and optional arguments allow the operator to specify encryption scope, speed, lateral movement, and post-encryption behaviors.

The binary accepts the following arguments:

The --full command-line argument appears to be the intended mode of operation for comprehensive file encryption on the infected device. When this argument is provided, the malware spawns two child processes of itself: one appended with the argument --system to encrypt local volumes under a SYSTEM-privileged scheduled task, and one appended with the argument --shares to encrypt network shares. This separation ensures that the malware can reach both local drives (which might require SYSTEM privileges) and mapped network shares (which are only visible in the user’s session).

The speed arguments (--fast, --superfast, --ultrafast) are mutually exclusive and control how much of each large file is encrypted. When no speed flag is specified, the default per-chunk percentage is 9%. These flags only affect files that are larger than 1 MB, and small files are fully encrypted regardless of the speed setting.

Usage prompt

When the encryptor is executed with no command-line argument, the malware prints a branded usage banner to the console.

It first executes the following PowerShell commands to render a console header:

This is followed by a detailed usage prompt provided by the malware author that documents all available flags with descriptions and examples:

It is worth noting that the file size percentages listed in the usage prompt refer to the total file encryption amount. Internally, the malware encrypts three separate chunks, and the per-chunk percentage used in the code is: fast=3%, superfast=1%, ultrafast=0.3%, default=9%.

Password check

Before executing its primary functionality, the malware validates the --password argument against a hardcoded value embedded within the binary. For the sample analyzed in this blog, the expected password is “9VoAvR7G”. If the provided password does not match, the malware outputs bad args and terminates execution.

This password check is a simple operator authentication mechanism, with each build containing a unique embedded password. Its purpose is to restrict execution to authorized operators and reduce the risk of accidental or unauthorized detonation if the binary is recovered or intercepted. However, because this validation relies on a static comparison, it can be easily identified and bypassed through static analysis techniques.

System encryption: Privilege escalation

When the --system argument is provided (either directly or via the --full argument), the malware creates a scheduled task to re-execute itself as SYSTEM. If a delay value is also specified through the --T argument, the scheduled execution time is adjusted accordingly.

To relaunch itself as SYSTEM, it issues the following sequence of commands:

The malware can only perform this task if it’s executed from an account with administrator privilege. It first deletes any existing task named gentlemen_system to avoid conflicts, creates a new one-time task that runs its binary under the SYSTEM account, and finally triggers that task.

This sequence ensures a clean state by first removing any existing task with the same name (gentlemen_system), creating a new scheduled task that executes the ransomware binary with SYSTEM-level privileges before finally triggering its immediate execution.

When running within this scheduled task context, the malware sets the environment variable LOCKER_BACKGROUND=1. This variable functions as an internal execution flag, indicating that the process is operating as a background encryption worker with elevated privileges, rather than as the original operator-invoked instance.

Defense evasion

Before starting file encryption, the malware executes a sequence of commands to disable defensive controls and remove potential forensic artifacts.

Disable Microsoft Defender

The PowerShell commands disable Microsoft Defender real-time monitoring to remove active protection on the infected device. The malware then adds its own executable to the Defender exclusion list to avoid detection. Finally, it excludes the entire C:\ volume from scanning, reducing the likelihood of subsequent detection during file encryption.

Delete shadow copies and event logs

To further impede recovery efforts, the malware deletes all Volume Shadow Copies using both vssadmin and wmic (Windows Management Instrumentation command-line utility). It then clears the System, Application, and Security event logs using wevtutil to remove key audit trails.

Delete forensics artifacts

These commands remove a variety of forensic artifacts, including prefetch files that track program execution, Defender diagnostic and support logs, and Remote Desktop Protocol (RDP) logs.

Additionally, the malware manually deletes PowerShell command history across all user profiles by removing the following file:

This action eliminates evidence of previously executed PowerShell commands, further reducing the visibility of execution history and threat actor activity.

Process and service termination

Process termination

The malware stops a list of running processes using the command:

The table below summarizes the different categories and processes being targeted:

Service termination

In addition to terminating processes, the malware disables and stops a list of Windows services using the commands:

The table below summarizes the different categories and services being targeted:

Terminating these processes and services serves two primary objectives:

• File access and encryption reliability: Many targeted processes/services, such as databases, Office applications, and backup agents, maintain active file locks. By forcibly terminating these processes, the ransomware ensures that locked files become accessible for encryption.
• Defense and recovery disruption: By stopping backup services, endpoint protection agents, and remote access tools, the malware reduces the likelihood of real-time detection and data restoration from backups.

Collectively, these behaviors maximize encryption coverage while hindering the environment’s ability to detect, respond to, or recover from the attack.

Persistence

The encryptor can establish persistence for itself through two mechanisms: scheduled tasks and registry keys.

Scheduled tasks persistence

For establishing persistence with scheduled tasks, the malware executes the following sequence of commands:

These commands first remove any pre-existing tasks with the same names, then create two persistence mechanisms that execute automatically at system startup. The UpdateSystem task launches the payload in the SYSTEM security context, while the UpdateUser task launches it in the currently signed-in user’s context. This design increases the likelihood that the ransomware will run after reboot regardless of privilege level or sign-in state.

Registry keys persistence

For establishing persistence with the registry, the malware executes the following sequence of commands:

The GupdateS value under HKEY_LOCAL_MACHINE (HKLM) provides device-wide persistence that allows the malware to run at startup for all users, while the GupdateU value under HKEY_CURRENT_USER (HKCU) provides user-scoped persistence within the current profile. By writing to both registry hives, the malware establishes redundant autorun paths across both system-level and user-level execution contexts.

Together, the scheduled tasks and Run key modifications create layered persistence, ensuring that the encryptor is re-executed after a reboot in both privileged and user-context scenarios.

Network share traversal

When the command-line argument --shares is provided, the malware initiates network share discovery and enumeration. It begins by probing all drive letters A through Z to identify mapped network drives using the following commands:

This sequence discovers any drives that are already mapped in the current user’s session, which are then added to the encryption target list.

To further enhance visibility into the network environment, the malware enables multiple Windows network discovery services and their associated firewall rules using the following commands:

The services enabled as part of this process include:

• Function Discovery Resource Publication (fdrespub): Publishes the host’s resources to the network, allowing other systems to detect it.
• Function Discovery Provider Host (fdPHost): Hosts provider components responsible for discovering network resources.
• Simple Service Discovery Protocol (SSDP) Discovery (SSDPSRV): Enables discovery of Universal Plug and Play (UPnP) devices.
• UPnP Device Host (upnphost): Supports the hosting and management of UPnP devices.

Finally, the malware reinforces this configuration by enabling the Network Discovery firewall rule group. This redundancy ensures that firewall restrictions do not limit its network visibility, further maximizing the number of reachable targets for encryption and propagation.

Volume and directory traversal

To enumerate all available volumes on the system, the malware executes the following PowerShell command sequence:

This command queries Windows Management Instrumentation (WMI) for all mounted volumes with drive letter paths and attempts to enumerate Cluster Shared Volumes (CSVs).

Additionally, the malware performs a secondary enumeration routine by iterating through drive letters A through Z while verifying their existence on disk. This brute-force method ensures broader coverage by identifying volumes that might not be retrieved through WMI queries to maximize visibility into all potential encryption targets.

Directory exclusion list

To maintain system stability and avoid disrupting critical operating system components, the malware excludes a predefined set of directories from traversal and encryption. These directories include core Windows system paths, application directories, and locations commonly associated with security and system management:

Extension exclusion list

The ransomware also excludes a set of file extensions associated with system-critical binaries, configuration files, and executable content:

By avoiding executable files, libraries, scripts, and other system-relevant formats, the malware preserves the integrity of the operating environment. This selective encryption model is a common ransomware design pattern, ensuring that the system remains operational enough for the victim to receive instructions and facilitate ransom payment.

File name exclusion list

The specific file names below are also excluded:

The inclusion of README-GENTLEMEN.txt, the ransomware’s ransom note, prevents it from being encrypted during execution. This ensures that the ransom instructions remain accessible to the victim, which is critical for the operator’s monetization workflow.

Ransom note

During directory traversal, the malware drops a ransom note named README-GENTLEMEN.txt in each scanned directory to provide victim-facing instructions.

The note contains identifiers assigned to the victim, communication channels, and guidance on how to initiate contact with the operators.

File encryption

File ownership

Before encrypting a file, the ransomware modifies the file ownership and access control settings to ensure it has unrestricted write access to the target. This is achieved through the following sequence of commands:

The takeown command recursively transfers ownership of the specified file or directory to the executing user, overriding existing ownership constraints. The icacls command then grants full control permissions to the Everyone security identifier (SID S-1-1-0), applying inheritance flags to propagate these permissions to all child objects. Finally, the attrib command removes the read-only attributes.

Cryptographic scheme

The Gentlemen ransomware implements a hybrid cryptographic design that combines Curve25519 elliptic-curve cryptography with the XChaCha20 stream cipher to achieve efficient and secure per-file encryption.

For each file, the malware performs the following sequence of operations:

1. Generates a unique ephemeral Curve25519 key pair, consisting of a randomly generated private key and its corresponding public key
2. Computes the Elliptic-curve Diffie–Hellman (ECDH) shared secret between the ephemeral private key and the operator’s embedded public key
3. Uses the resulting shared secret as the XChaCha20 key, and derives the nonce from the first 24 bytes of the ephemeral public key
4. Encrypts the file contents using XChaCha20 with this key and nonce combination
5. Appends the Base64-encoded ephemeral public key to the file footer to enable subsequent key reconstruction during decryption

In this sample, the operator’s public key is hard-coded within the binary as a Base64-encoded value:

This design ensures that each file is encrypted with a distinct key and nonce derived from a per-file ephemeral key exchange, eliminating any possibility of key or nonce reuse across files.

During decryption, the decryptor can use the operator’s Curve25519 private key together with the stored ephemeral public key to reconstruct the ECDH shared secret and recover the XChaCha20 key. The nonce is deterministically reconstructed by extracting the first 24 bytes of the recovered ephemeral public key, making separate nonce storage unnecessary.

Overall, this approach provides strong cryptographic isolation between encrypted files while maintaining operational simplicity and efficiency for the threat actor during both encryption and decryption.

Size-based encryption

The malware uses different encryption strategies based on file size:

Small files that are less than 1MB in size are fully encrypted. This ensures that documents, configuration files, and other small but critical data are completely corrupted. For larger files such as databases, virtual disk images, archives, full encryption would be time-consuming. Instead, the malware encrypts three data chunks distributed across the file, which is sufficient to corrupt the file structure while dramatically reducing encryption time.

After encryption, each affected file is renamed with the appended extension .umc16h. This extension serves as a quick indicator of files already encrypted by the ransomware.

Large file chunking logic

For files larger than 1 MB, the malware performs partial encryption by dividing the file into three non-contiguous chunks distributed across its contents:

The first chunk begins at the start of the file, the second is positioned near the midpoint, and the third is located toward the end. This distribution ensures that even limited encryption is sufficient to corrupt the file structure while minimizing processing time.

Each chunk is encrypted in 64 KB (0x10000) blocks using XChaCha20. To maintain cryptographic separation between chunks, the malware modifies the nonce on a per-chunk basis. Specifically, the last byte of the 24-byte XChaCha20 nonce is XOR-ed with the chunk index (0, 1, or 2), and a new cipher instance is initialized for each chunk using the modified nonce. As a result, chunk 0 uses the original nonce, while subsequent chunks use deterministically altered variants.

Although all chunks for a given file share the same derived encryption key, this nonce mutation ensures that each chunk is processed under a unique keystream, preventing keystream reuse across different regions of the file.

The encryption percentage for each file is determined by the provided speed command-line arguments:

File footer

After encrypting each file, the malware appends a structured footer containing metadata required for identification and decryption. The footer format differs slightly depending on whether the file was fully or partially encrypted.

Small file encryption (files ≤ 1 MB):

Large file encryption (files > 1 MB):

The footer serves three primary functions:

1. Key and nonce reconstruction: The Base64-encoded ephemeral public key, located after --eph--, allows the decryptor to recompute both the XChaCha20 key (using ECDH shared secret) and the nonce (first 24 bytes of the ephemeral public key).
2. Identification: The GENTLEMEN marker, located after --marker--, serves as a unique identifier, allowing encryptors/decryptors to quickly determine that the file has been encrypted by The Gentlemen ransomware.
3. Decryption mode: The optional speed flag marker (only present on large files) tells the decryptor which chunking percentage was used.

Notably, the speed marker is only present for large-file encryption. Files that are ≤ 1 MB do not include a speed marker, and its absence signals that the file was fully encrypted. This implicit encoding in the footer allows the decryptor to distinguish between full and partial encryption modes without requiring additional metadata fields.

Post-encryption

Wallpaper setup

If the --silent argument is not provided, the malware drops the following bitmap image file to %TEMP%\gentlemen.bmp and sets it as the system’s desktop wallpaper.

This behavior serves as an immediate visual indicator of compromise, signaling to the victim that encryption has completed.

Self-propagation

The self-propagation module is the more distinctive component of The Gentlemen ransomware. When enabled with the --spread argument, it turns the malware from a single-host encryptor into a self-propagating worm that attempts to deploy its encryptor to every reachable system on the network.

The --spread argument accepts either explicit credentials in domain/user:password format for authenticated lateral movement, or an empty string to reuse the current session’s authentication token.

Placeholder legend

The executed commands in this section use the following placeholders:

Phase 1: Local staging setup

The malware prepares the infected host to act as a distribution point for its binary by executing the following command sequence:

The commands copy the malware executable into C:\Temp, creates a hidden Server Message Block (SMB) share named share$ pointing to that directory, and modifies registry settings to allow anonymous access. With this setup, other systems on the network can retrieve the payload from \\<self>\share$, even when valid credentials are not available.

Phase 2: PsExec drop

The malware binary carries an embedded copy of PsExec and drops it to C:\Temp\psexec.exe on the infected device.

If the embedded PsExec payload cannot be extracted successfully, the malware falls back to downloading PsExec directly from Microsoft’s Sysinternals Live service using the following PowerShell command:

Phase 3: Network enumeration

After dropping PsExec, the malware attempts to enumerate and discover remote systems on the network, including workstations, servers, and domain controllers. Each discovered host becomes a candidate target for propagation.

Phase 4: PowerShell defense evasion blob

Before attempting to run the payload on a remote system, the malware executes the following PowerShell command on the remote target to weaken local defenses and make payload execution more reliable:

This command disables Microsoft Defender real-time monitoring, adds broad Defender exclusions, turns off Windows Firewall across all profiles, shares local drives, grants permissive New Technology File System (NTFS) access, enables SMB1, and loosens anonymous-access restrictions through Local Security Authority (LSA) registry settings. Together, these changes make the remote system significantly more exposed and ready for the payload deployment step.

Phase 5: Payload deployment

For each discovered remote host, the malware attempts a series of independent lateral movement techniques to execute its payload. Notably, these techniques are executed without dependency on prior success, and each method is attempted regardless of whether earlier attempts fail. This execution model of The Gentlemen’s propagation logic can significantly increase the likelihood that at least one execution path succeeds even in secured environments.

5.1: Remote file copy

The malware first stages its payload on the remote system by copying the encryptor binary over the administrative C$ share:

This operation ensures a local copy of the payload is available on the target host, allowing subsequent execution methods to reference a path that does not depend on network shares.

5.2: PsExec-based execution

If PsExec is successfully dropped or downloaded, the malware leverages it to perform a multi-stage execution sequence on the remote host.

First, the malware executes the PowerShell defense evasion payload to weaken host protections:

After a delay to allow defenses to be disabled, the malware executes the payload from the locally staged path C:\Temp under SYSTEM privileges:

After another sleep period, the malware executes the final command to run the payload with the –h flag for elevated token and –c -f to copy and force execution:

5.3: WMIC process creation

The malware uses WMI via wmic.exe to create remote processes:

The first command executes the defense evasion blob, the second runs the payload from the infected host’s SMB share, and the third runs the pre-staged copy from the target’s local C:\Temp directory.

5.4: Scheduled tasks (user)

The malware creates three scheduled tasks under the target user’s context, each running two minutes after the time when they are created:

The scheduled task DefU is set to run the defense evasion blob, UpdateGU executes the payload from the infected host’s SMB share, and UpdateGU2runs the pre-staged copy from the target’s local C:\Temp directory.

5.5: Scheduled tasks (system)

The same three tasks are repeated, running under the SYSTEM account:

By attempting both user-context and SYSTEM-context task creation, the ransomware can improve its chance of propagation across environments with different permission boundaries.

5.6: Service-based execution

The malware executes the following command sequence to create three Windows services on the target host:

Similar to the scheduled tasks, the service DefSvc is set to run the defense evasion blob, UpdateSvc executes the payload from the infected host’s SMB share, and UpdateSvc2 runs the pre-staged copy from the target’s local C:\Temp directory. These services run as SYSTEM by default, which provides another high-privilege execution path for the ransomware payload on the remote system.

5.7: Payload deployment: PowerShell remoting

Using PowerShell remoting, the malware executes commands directly on the target using Invoke-Command:

This method leverages Windows Remote Management (WinRM), providing an alternative execution channel when PsExec or WMIC are unavailable or blocked.

5.8: PowerShell WMI execution

Finally, the malware uses the PowerShell WMI class interface directly to create remote processes with the following command sequence.

This provides functionality equivalent to wmic.exe, but through a different execution path. As a result, it might succeed in environments where the WMIC binary is restricted but WMI access remains available.

Self-propagation summary

Across all techniques, the malware attempts 21 remote execution operations per target host, spanning multiple APIs, privilege levels, and execution contexts. Each method attempts to launch the payload from:

• The infected host’s SMB share: \\<self>\share$\<payload_name>
• The target host’s locally staged path: C:\Temp\<payload_name>

This redundancy is central to The Gentlemen’s propagation strategy. In secured environments where most lateral movement techniques are mitigated, a single successful execution on a single additional host is sufficient to continue the propagation.

Free space wipe

If the --wipe argument is provided, The Gentlemen ransomware performs an additional post-encryption routine to eliminate recoverable artifacts from disk.

The malware first enumerates all available volume paths on the system. For each volume, it creates a temporary file named wipefile.tmp at the root directory and determines the amount of available free space. It then writes random data to this file in 64 MB blocks until the volume is completely filled. Once the disk space has been exhausted, the temporary file is deleted.

This process effectively overwrites all unallocated disk space with random data, preventing forensic tools from recovering remnants of previously deleted files. This includes cached or temporary versions of original unencrypted data that might still reside on disk. When combined with earlier actions such as Volume Shadow Copy deletion, this behavior reduces the likelihood of data recovery without access to the threat actor’s decryption key.

Self-delete

If the --keep flag is not provided, the malware attempts to remove its executable from disk after completing encryption.

Since a running process cannot directly delete its own binary, the ransomware generates and executes a temporary batch script at <malware_path>.batwith the following contents:

The batch script introduces a short delay by sending three Internet Control Message Protocol (ICMP) echo requests to the local host, pausing execution long enough for the main malware process to terminate. After this delay, the script deletes the original ransomware executable before removing itself. This mechanism helps reduce on-disk artifacts and hinders post-incident forensic analysis by eliminating the ransomware binary from the compromised system.

Defending against The Gentlemen ransomware

Microsoft recommends the following mitigations to reduce the impact of this threat.

• Read the human-operated ransomware threat overview for advice on developing a holistic security posture to prevent ransomware, including credential hygiene and hardening recommendations. 
• Turn on cloud-delivered protection in Microsoft Defender Antivirus or the equivalent for your antivirus product to cover rapidly evolving threat actor tools and techniques. Cloud-based machine learning protections block a huge majority of new and unknown variants. 
• Turn on tamper protection features to prevent threat actors from stopping security services. In addition to tamper protection, you can also enable and configure Microsoft Defender Antivirus always-on protection in Group Policy. 
• Enable controlled folder access. Controlled folder access helps protect your valuable data from malicious apps and threats, such as ransomware. Controlled folder access works by only allowing trusted apps to access protected folders. Protected folders are specified when controlled folder access is configured. Apps that aren’t included in the trusted apps list are prevented from making any changes to files inside protected folders. 
• Run endpoint detection and response (EDR) in block mode so that Microsoft Defender for Endpoint can block malicious artifacts, even when your non-Microsoft antivirus does not detect the threat or when Microsoft Defender Antivirus is running in passive mode. EDR in block mode works behind the scenes to remediate malicious artifacts that are detected post-breach. 
• Configure investigation and remediation in full automated mode to let Microsoft Defender for Endpoint take immediate action on alerts to resolve breaches, significantly reducing alert volume. 
• Configure automatic attack disruption in Microsoft Defender XDR. Automatic attack disruption is designed to contain attacks in progress, limit the impact on an organization’s assets, and provide more time for security teams to remediate the attack fully. 
• Microsoft Defender XDR customers can turn on attack surface reduction rules to prevent several of the infection vectors of this threat. These rules, which can be configured by any user, offer significant hardening against targeted attacks. In observed attacks, Microsoft customers who had the following rules turned on could mitigate the attack in the initial stages and prevent hands-on-keyboard activity:  
  • Block executable files from running unless they meet a prevalence, age, or trusted list criterion 
  • Block process creations originating from PSExec and WMI commands if you’re managing your devices with Intune or another MDM solution. This rule is incompatible with management through Microsoft Endpoint Configuration Manager. 
  • Use advanced protection against ransomware

Microsoft Defender detections and hunting guidance

Microsoft Defender customers can refer to the list of applicable detections below. Microsoft Defender coordinates detection, prevention, investigation, and response across endpoints, identities, email, apps to provide integrated protection against attacks like the threat discussed in this blog.

Microsoft Defender Antivirus

Microsoft Defender Antivirus detects threat components as the following malware:

• Ransom:Win64/Gentlemen

Microsoft Defender for Endpoint

The following alerts might indicate threat activity associated with this threat. These alerts, however, can be triggered by unrelated threat activity and are not monitored in the status cards provided with this report.

• Ransomware-linked threat actor detected
• Ransomware behavior detected in the file system
• Possible ransomware activity
• File backups were deleted
• Potential human-operated malicious activity
• Possible data exfiltration
• Suspicious wallpaper change

The following alerts might indicate threat activity associated with The Gentlemen ransomware if Defender for Endpoint is set to block mode.

• ‘Gentlemen’ ransomware was detected
• ‘Gentlemen’ ransomware was prevented

Microsoft Defender for Cloud Apps

The following alert might indicate threat activity associated with this threat. This alert, however, can be triggered by unrelated threat activity and are not monitored in the status cards provided with this report.

• Ransomware activity

Microsoft Security Copilot

Microsoft Security Copilot is embedded in Microsoft Defender and provides security teams with AI-powered capabilities to summarize incidents, analyze files and scripts, summarize identities, use guided responses, and generate device summaries, hunting queries, and incident reports.

Customers can also deploy AI agents, including the following Microsoft Security Copilot agents, to perform security tasks efficiently:

• Threat Intelligence Briefing agent
• Phishing Triage agent
• Threat Hunting agent
• Dynamic Threat Detection agent

Security Copilot is also available as a standalone experience where customers can perform specific security-related tasks, such as incident investigation, user analysis, and vulnerability impact assessment. In addition, Security Copilot offers developer scenarios that allow customers to build, test, publish, and integrate AI agents and plugins to meet unique security needs.

Threat intelligence reports

Microsoft Defender XDR customers can use the following threat analytics reports in the Defender portal (requires license for at least one Defender XDR product) to get the most up-to-date information about the threat actor, malicious activity, and techniques discussed in this blog. These reports provide the intelligence, protection information, and recommended actions to prevent, mitigate, or respond to associated threats found in customer environments.

Microsoft Defender XDR threat analytics

• Tool profile: Gentlemen ransomware
• Threat overview profile: Human-operated ransomware

Microsoft Security Copilot customers can also use the Microsoft Security Copilot integration in Microsoft Defender Threat Intelligence, either in the Security Copilot standalone portal or in the embedded experience in the Microsoft Defender portal to get more information about this threat actor.

Hunting queries

Microsoft Defender XDR

Microsoft Defender XDR customers can run the following advanced hunting queries to find related activity in their networks:

Known The Gentlemen ransomware files

Search for the file hashes associated with The Gentlemen ransomware activity identified in this report. 

let fileHashes = dynamic(["22b38dad7da097ea03aa28d0614164cd25fafeb1383dbc15047e34c8050f6f67"]);
union
(
   DeviceFileEvents
   | where SHA256 in (fileHashes)
   | project Timestamp, DeviceId, DeviceName, FileName, InitiatingProcessFileName, FileHash = SHA256, SourceTable = "DeviceFileEvents"
),
(
   DeviceEvents
   | where SHA256 in (fileHashes)
   | project Timestamp, DeviceId, DeviceName, FileName, InitiatingProcessFileName, FileHash = 
SHA256, SourceTable = "DeviceEvents"
),
(
   DeviceImageLoadEvents
   | where SHA256 in (fileHashes)
   | project Timestamp, DeviceId, DeviceName, FileName, InitiatingProcessFileName, FileHash = SHA256, SourceTable = "DeviceImageLoadEvents"
),
(
   DeviceProcessEvents
   | where SHA256 in (fileHashes)
   | project Timestamp, DeviceId, DeviceName, FileName, InitiatingProcessFileName, FileHash = SHA256, SourceTable = "DeviceProcessEvents"
)
| order by Timestamp desc

Microsoft Sentinel

Microsoft Sentinel customers can use the TI Mapping analytics (a series of analytics all prefixed with ‘TI map’) to automatically match the malicious domain indicators mentioned in this blog post with data in their workspace. If the TI Map analytics are not currently deployed, customers can install the Threat Intelligence solution from the Microsoft Sentinel Content Hub to have the analytics rule deployed in their Sentinel workspace.

Detect web sessions IP and file hash indicators of compromise using Advanced Security Information Model (ASIM)

The following query checks IP addresses, domains, and file hash IOCs across data sources supported by ASIM web session parser:

//IP list - _Im_WebSession
let lookback = 30d;
let ioc_ip_addr = dynamic([]);
let ioc_sha_hashes =dynamic(["22b38dad7da097ea03aa28d0614164cd25fafeb1383dbc15047e34c8050f6f67"]);
_Im_WebSession(starttime=todatetime(ago(lookback)), endtime=now())
| where DstIpAddr in (ioc_ip_addr) or FileSHA256 in (ioc_sha_hashes)
| summarize imWS_mintime=min(TimeGenerated), imWS_maxtime=max(TimeGenerated),
  EventCount=count() by SrcIpAddr, DstIpAddr, Url, Dvc, EventProduct, EventVendor

Detect files hashes indicators of compromise using ASIM

The following query checks IP addresses and file hash IOCs across data sources supported by ASIM file event parser:

// file hash list - imFileEvent
let ioc_sha_hashes = dynamic(["22b38dad7da097ea03aa28d0614164cd25fafeb1383dbc15047e34c8050f6f67"]);
imFileEvent
| where SrcFileSHA256 in (ioc_sha_hashes) or
TargetFileSHA256 in (ioc_sha_hashes)
| extend AccountName = tostring(split(User, @'')[1]), 
  AccountNTDomain = tostring(split(User, @'')[0])
| extend AlgorithmType = "SHA256"

Indicators of compromise

Acknowledgements

• License to Encrypt: The “Gentlemen” Make Their Move. Cybereason (accessed 2026-02-06)
• Unmasking The Gentlemen Ransomware: Tactics, Techniques, and Procedures Revealed. TrendMicro (accessed 2026-02-06)

Learn more

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The post The Gentlemen ransomware: Dissecting a self-propagating Go encryptor appeared first on Microsoft Security Blog.

Ransomware that combines robust encryption with rapid lateral movement significantly increases the risk and impact of an attack. The Gentlemen ransomware is a ransomware-as-a-service (RaaS) threat that is distinguished by its ability to pair its strong per-file encryption with an aggressive self-propagation capability designed to enable broad network compromise. In addition to using per-file ephemeral Curve25519 keys with XChaCha20 stream cipher, The Gentlemen ransomware attempts to spread across an environment using series of simultaneous, distinct lateral movement methods, increasing the likelihood of widespread impact once initial access is achieved.

Microsoft Threat Intelligence tracks the operators behind the ransomware as Storm-2697, a financially motivated threat actor that manages the RaaS platform known as “The Gentlemen” while affiliates carry out attacks. Emerging around mid-2025, The Gentlemen initially started as a closed ransomware group then began offering its RaaS to affiliates in September 2025. More recently, The Gentlemen operators established an official partnership with BreachForums, a popular cybercriminal marketplace, to recruit affiliates including penetration testers and initial access brokers. Given that The Gentlemen is already a widely adopted RaaS platform, this partnership may lead to increased activity as the program becomes accessible to a broader pool of threat actors.

The operators behind the ransomware use double extortion tactics, encrypting data while also exfiltrating sensitive information to pressure victims through the threat of public release if the ransom is not paid. The ransomware is written in Go and obfuscated with Garble to target the Windows environment. Microsoft has observed The Gentlemen ransomware impacting organizations across education, transportation, healthcare, and financial industries in North America, South America, Europe, Africa, and Asia.

In this blog, we present a detailed analysis of the Gentlemen ransomware encryptor, including its execution flow, defense evasion behaviors, encryption design, and lateral movement techniques. This research is intended to provide defenders, incident responders, and the broader security community with a better understanding of how the threat operates, from initial argument parsing and defense evasion, through its file encryption internals, to the full lateral movement that enables it to propagate across the network. We also provide mitigation guidance, Microsoft Defender detections, hunting queries, and indicators of compromise (IOCs) to help organizations defend against this threat and similar ransomware activity.

Pre-encryption

Command-line argument processing

The ransomware operator can control The Gentlemen encryptor through command-line arguments. A password is required for execution, and optional arguments allow the operator to specify encryption scope, speed, lateral movement, and post-encryption behaviors.

The binary accepts the following arguments:

The --full command-line argument appears to be the intended mode of operation for comprehensive file encryption on the infected device. When this argument is provided, the malware spawns two child processes of itself: one appended with the argument --system to encrypt local volumes under a SYSTEM-privileged scheduled task, and one appended with the argument --shares to encrypt network shares. This separation ensures that the malware can reach both local drives (which might require SYSTEM privileges) and mapped network shares (which are only visible in the user’s session).

The speed arguments (--fast, --superfast, --ultrafast) are mutually exclusive and control how much of each large file is encrypted. When no speed flag is specified, the default per-chunk percentage is 9%. These flags only affect files that are larger than 1 MB, and small files are fully encrypted regardless of the speed setting.

Usage prompt

When the encryptor is executed with no command-line argument, the malware prints a branded usage banner to the console.

It first executes the following PowerShell commands to render a console header:

This is followed by a detailed usage prompt provided by the malware author that documents all available flags with descriptions and examples:

It is worth noting that the file size percentages listed in the usage prompt refer to the total file encryption amount. Internally, the malware encrypts three separate chunks, and the per-chunk percentage used in the code is: fast=3%, superfast=1%, ultrafast=0.3%, default=9%.

Password check

Before executing its primary functionality, the malware validates the --password argument against a hardcoded value embedded within the binary. For the sample analyzed in this blog, the expected password is “9VoAvR7G”. If the provided password does not match, the malware outputs bad args and terminates execution.

This password check is a simple operator authentication mechanism, with each build containing a unique embedded password. Its purpose is to restrict execution to authorized operators and reduce the risk of accidental or unauthorized detonation if the binary is recovered or intercepted. However, because this validation relies on a static comparison, it can be easily identified and bypassed through static analysis techniques.

System encryption: Privilege escalation

When the --system argument is provided (either directly or via the --full argument), the malware creates a scheduled task to re-execute itself as SYSTEM. If a delay value is also specified through the --T argument, the scheduled execution time is adjusted accordingly.

To relaunch itself as SYSTEM, it issues the following sequence of commands:

The malware can only perform this task if it’s executed from an account with administrator privilege. It first deletes any existing task named gentlemen_system to avoid conflicts, creates a new one-time task that runs its binary under the SYSTEM account, and finally triggers that task.

This sequence ensures a clean state by first removing any existing task with the same name (gentlemen_system), creating a new scheduled task that executes the ransomware binary with SYSTEM-level privileges before finally triggering its immediate execution.

When running within this scheduled task context, the malware sets the environment variable LOCKER_BACKGROUND=1. This variable functions as an internal execution flag, indicating that the process is operating as a background encryption worker with elevated privileges, rather than as the original operator-invoked instance.

Defense evasion

Before starting file encryption, the malware executes a sequence of commands to disable defensive controls and remove potential forensic artifacts.

Disable Microsoft Defender

The PowerShell commands disable Microsoft Defender real-time monitoring to remove active protection on the infected device. The malware then adds its own executable to the Defender exclusion list to avoid detection. Finally, it excludes the entire C:\ volume from scanning, reducing the likelihood of subsequent detection during file encryption.

Delete shadow copies and event logs

To further impede recovery efforts, the malware deletes all Volume Shadow Copies using both vssadmin and wmic (Windows Management Instrumentation command-line utility). It then clears the System, Application, and Security event logs using wevtutil to remove key audit trails.

Delete forensics artifacts

These commands remove a variety of forensic artifacts, including prefetch files that track program execution, Defender diagnostic and support logs, and Remote Desktop Protocol (RDP) logs.

Additionally, the malware manually deletes PowerShell command history across all user profiles by removing the following file:

This action eliminates evidence of previously executed PowerShell commands, further reducing the visibility of execution history and threat actor activity.

Process and service termination

Process termination

The malware stops a list of running processes using the command:

The table below summarizes the different categories and processes being targeted:

Service termination

In addition to terminating processes, the malware disables and stops a list of Windows services using the commands:

The table below summarizes the different categories and services being targeted:

Terminating these processes and services serves two primary objectives:

• File access and encryption reliability: Many targeted processes/services, such as databases, Office applications, and backup agents, maintain active file locks. By forcibly terminating these processes, the ransomware ensures that locked files become accessible for encryption.
• Defense and recovery disruption: By stopping backup services, endpoint protection agents, and remote access tools, the malware reduces the likelihood of real-time detection and data restoration from backups.

Collectively, these behaviors maximize encryption coverage while hindering the environment’s ability to detect, respond to, or recover from the attack.

Persistence

The encryptor can establish persistence for itself through two mechanisms: scheduled tasks and registry keys.

Scheduled tasks persistence

For establishing persistence with scheduled tasks, the malware executes the following sequence of commands:

These commands first remove any pre-existing tasks with the same names, then create two persistence mechanisms that execute automatically at system startup. The UpdateSystem task launches the payload in the SYSTEM security context, while the UpdateUser task launches it in the currently signed-in user’s context. This design increases the likelihood that the ransomware will run after reboot regardless of privilege level or sign-in state.

Registry keys persistence

For establishing persistence with the registry, the malware executes the following sequence of commands:

The GupdateS value under HKEY_LOCAL_MACHINE (HKLM) provides device-wide persistence that allows the malware to run at startup for all users, while the GupdateU value under HKEY_CURRENT_USER (HKCU) provides user-scoped persistence within the current profile. By writing to both registry hives, the malware establishes redundant autorun paths across both system-level and user-level execution contexts.

Together, the scheduled tasks and Run key modifications create layered persistence, ensuring that the encryptor is re-executed after a reboot in both privileged and user-context scenarios.

Network share traversal

When the command-line argument --shares is provided, the malware initiates network share discovery and enumeration. It begins by probing all drive letters A through Z to identify mapped network drives using the following commands:

This sequence discovers any drives that are already mapped in the current user’s session, which are then added to the encryption target list.

To further enhance visibility into the network environment, the malware enables multiple Windows network discovery services and their associated firewall rules using the following commands:

The services enabled as part of this process include:

• Function Discovery Resource Publication (fdrespub): Publishes the host’s resources to the network, allowing other systems to detect it.
• Function Discovery Provider Host (fdPHost): Hosts provider components responsible for discovering network resources.
• Simple Service Discovery Protocol (SSDP) Discovery (SSDPSRV): Enables discovery of Universal Plug and Play (UPnP) devices.
• UPnP Device Host (upnphost): Supports the hosting and management of UPnP devices.

Finally, the malware reinforces this configuration by enabling the Network Discovery firewall rule group. This redundancy ensures that firewall restrictions do not limit its network visibility, further maximizing the number of reachable targets for encryption and propagation.

Volume and directory traversal

To enumerate all available volumes on the system, the malware executes the following PowerShell command sequence:

This command queries Windows Management Instrumentation (WMI) for all mounted volumes with drive letter paths and attempts to enumerate Cluster Shared Volumes (CSVs).

Additionally, the malware performs a secondary enumeration routine by iterating through drive letters A through Z while verifying their existence on disk. This brute-force method ensures broader coverage by identifying volumes that might not be retrieved through WMI queries to maximize visibility into all potential encryption targets.

Directory exclusion list

To maintain system stability and avoid disrupting critical operating system components, the malware excludes a predefined set of directories from traversal and encryption. These directories include core Windows system paths, application directories, and locations commonly associated with security and system management:

Extension exclusion list

The ransomware also excludes a set of file extensions associated with system-critical binaries, configuration files, and executable content:

By avoiding executable files, libraries, scripts, and other system-relevant formats, the malware preserves the integrity of the operating environment. This selective encryption model is a common ransomware design pattern, ensuring that the system remains operational enough for the victim to receive instructions and facilitate ransom payment.

File name exclusion list

The specific file names below are also excluded:

The inclusion of README-GENTLEMEN.txt, the ransomware’s ransom note, prevents it from being encrypted during execution. This ensures that the ransom instructions remain accessible to the victim, which is critical for the operator’s monetization workflow.

Ransom note

During directory traversal, the malware drops a ransom note named README-GENTLEMEN.txt in each scanned directory to provide victim-facing instructions.

The note contains identifiers assigned to the victim, communication channels, and guidance on how to initiate contact with the operators.

File encryption

File ownership

Before encrypting a file, the ransomware modifies the file ownership and access control settings to ensure it has unrestricted write access to the target. This is achieved through the following sequence of commands:

The takeown command recursively transfers ownership of the specified file or directory to the executing user, overriding existing ownership constraints. The icacls command then grants full control permissions to the Everyone security identifier (SID S-1-1-0), applying inheritance flags to propagate these permissions to all child objects. Finally, the attrib command removes the read-only attributes.

Cryptographic scheme

The Gentlemen ransomware implements a hybrid cryptographic design that combines Curve25519 elliptic-curve cryptography with the XChaCha20 stream cipher to achieve efficient and secure per-file encryption.

For each file, the malware performs the following sequence of operations:

1. Generates a unique ephemeral Curve25519 key pair, consisting of a randomly generated private key and its corresponding public key
2. Computes the Elliptic-curve Diffie–Hellman (ECDH) shared secret between the ephemeral private key and the operator’s embedded public key
3. Uses the resulting shared secret as the XChaCha20 key, and derives the nonce from the first 24 bytes of the ephemeral public key
4. Encrypts the file contents using XChaCha20 with this key and nonce combination
5. Appends the Base64-encoded ephemeral public key to the file footer to enable subsequent key reconstruction during decryption

In this sample, the operator’s public key is hard-coded within the binary as a Base64-encoded value:

This design ensures that each file is encrypted with a distinct key and nonce derived from a per-file ephemeral key exchange, eliminating any possibility of key or nonce reuse across files.

During decryption, the decryptor can use the operator’s Curve25519 private key together with the stored ephemeral public key to reconstruct the ECDH shared secret and recover the XChaCha20 key. The nonce is deterministically reconstructed by extracting the first 24 bytes of the recovered ephemeral public key, making separate nonce storage unnecessary.

Overall, this approach provides strong cryptographic isolation between encrypted files while maintaining operational simplicity and efficiency for the threat actor during both encryption and decryption.

Size-based encryption

The malware uses different encryption strategies based on file size:

Small files that are less than 1MB in size are fully encrypted. This ensures that documents, configuration files, and other small but critical data are completely corrupted. For larger files such as databases, virtual disk images, archives, full encryption would be time-consuming. Instead, the malware encrypts three data chunks distributed across the file, which is sufficient to corrupt the file structure while dramatically reducing encryption time.

After encryption, each affected file is renamed with the appended extension .umc16h. This extension serves as a quick indicator of files already encrypted by the ransomware.

Large file chunking logic

For files larger than 1 MB, the malware performs partial encryption by dividing the file into three non-contiguous chunks distributed across its contents:

The first chunk begins at the start of the file, the second is positioned near the midpoint, and the third is located toward the end. This distribution ensures that even limited encryption is sufficient to corrupt the file structure while minimizing processing time.

Each chunk is encrypted in 64 KB (0x10000) blocks using XChaCha20. To maintain cryptographic separation between chunks, the malware modifies the nonce on a per-chunk basis. Specifically, the last byte of the 24-byte XChaCha20 nonce is XOR-ed with the chunk index (0, 1, or 2), and a new cipher instance is initialized for each chunk using the modified nonce. As a result, chunk 0 uses the original nonce, while subsequent chunks use deterministically altered variants.

Although all chunks for a given file share the same derived encryption key, this nonce mutation ensures that each chunk is processed under a unique keystream, preventing keystream reuse across different regions of the file.

The encryption percentage for each file is determined by the provided speed command-line arguments:

File footer

After encrypting each file, the malware appends a structured footer containing metadata required for identification and decryption. The footer format differs slightly depending on whether the file was fully or partially encrypted.

Small file encryption (files ≤ 1 MB):

Large file encryption (files > 1 MB):

The footer serves three primary functions:

1. Key and nonce reconstruction: The Base64-encoded ephemeral public key, located after --eph--, allows the decryptor to recompute both the XChaCha20 key (using ECDH shared secret) and the nonce (first 24 bytes of the ephemeral public key).
2. Identification: The GENTLEMEN marker, located after --marker--, serves as a unique identifier, allowing encryptors/decryptors to quickly determine that the file has been encrypted by The Gentlemen ransomware.
3. Decryption mode: The optional speed flag marker (only present on large files) tells the decryptor which chunking percentage was used.

Notably, the speed marker is only present for large-file encryption. Files that are ≤ 1 MB do not include a speed marker, and its absence signals that the file was fully encrypted. This implicit encoding in the footer allows the decryptor to distinguish between full and partial encryption modes without requiring additional metadata fields.

Post-encryption

Wallpaper setup

If the --silent argument is not provided, the malware drops the following bitmap image file to %TEMP%\gentlemen.bmp and sets it as the system’s desktop wallpaper.

This behavior serves as an immediate visual indicator of compromise, signaling to the victim that encryption has completed.

Self-propagation

The self-propagation module is the more distinctive component of The Gentlemen ransomware. When enabled with the --spread argument, it turns the malware from a single-host encryptor into a self-propagating worm that attempts to deploy its encryptor to every reachable system on the network.

The --spread argument accepts either explicit credentials in domain/user:password format for authenticated lateral movement, or an empty string to reuse the current session’s authentication token.

Placeholder legend

The executed commands in this section use the following placeholders:

Phase 1: Local staging setup

The malware prepares the infected host to act as a distribution point for its binary by executing the following command sequence:

The commands copy the malware executable into C:\Temp, creates a hidden Server Message Block (SMB) share named share$ pointing to that directory, and modifies registry settings to allow anonymous access. With this setup, other systems on the network can retrieve the payload from \\<self>\share$, even when valid credentials are not available.

Phase 2: PsExec drop

The malware binary carries an embedded copy of PsExec and drops it to C:\Temp\psexec.exe on the infected device.

If the embedded PsExec payload cannot be extracted successfully, the malware falls back to downloading PsExec directly from Microsoft’s Sysinternals Live service using the following PowerShell command:

Phase 3: Network enumeration

After dropping PsExec, the malware attempts to enumerate and discover remote systems on the network, including workstations, servers, and domain controllers. Each discovered host becomes a candidate target for propagation.

Phase 4: PowerShell defense evasion blob

Before attempting to run the payload on a remote system, the malware executes the following PowerShell command on the remote target to weaken local defenses and make payload execution more reliable:

This command disables Microsoft Defender real-time monitoring, adds broad Defender exclusions, turns off Windows Firewall across all profiles, shares local drives, grants permissive New Technology File System (NTFS) access, enables SMB1, and loosens anonymous-access restrictions through Local Security Authority (LSA) registry settings. Together, these changes make the remote system significantly more exposed and ready for the payload deployment step.

Phase 5: Payload deployment

For each discovered remote host, the malware attempts a series of independent lateral movement techniques to execute its payload. Notably, these techniques are executed without dependency on prior success, and each method is attempted regardless of whether earlier attempts fail. This execution model of The Gentlemen’s propagation logic can significantly increase the likelihood that at least one execution path succeeds even in secured environments.

5.1: Remote file copy

The malware first stages its payload on the remote system by copying the encryptor binary over the administrative C$ share:

This operation ensures a local copy of the payload is available on the target host, allowing subsequent execution methods to reference a path that does not depend on network shares.

5.2: PsExec-based execution

If PsExec is successfully dropped or downloaded, the malware leverages it to perform a multi-stage execution sequence on the remote host.

First, the malware executes the PowerShell defense evasion payload to weaken host protections:

After a delay to allow defenses to be disabled, the malware executes the payload from the locally staged path C:\Temp under SYSTEM privileges:

After another sleep period, the malware executes the final command to run the payload with the –h flag for elevated token and –c -f to copy and force execution:

5.3: WMIC process creation

The malware uses WMI via wmic.exe to create remote processes:

The first command executes the defense evasion blob, the second runs the payload from the infected host’s SMB share, and the third runs the pre-staged copy from the target’s local C:\Temp directory.

5.4: Scheduled tasks (user)

The malware creates three scheduled tasks under the target user’s context, each running two minutes after the time when they are created:

The scheduled task DefU is set to run the defense evasion blob, UpdateGU executes the payload from the infected host’s SMB share, and UpdateGU2runs the pre-staged copy from the target’s local C:\Temp directory.

5.5: Scheduled tasks (system)

The same three tasks are repeated, running under the SYSTEM account:

By attempting both user-context and SYSTEM-context task creation, the ransomware can improve its chance of propagation across environments with different permission boundaries.

5.6: Service-based execution

The malware executes the following command sequence to create three Windows services on the target host:

Similar to the scheduled tasks, the service DefSvc is set to run the defense evasion blob, UpdateSvc executes the payload from the infected host’s SMB share, and UpdateSvc2 runs the pre-staged copy from the target’s local C:\Temp directory. These services run as SYSTEM by default, which provides another high-privilege execution path for the ransomware payload on the remote system.

5.7: Payload deployment: PowerShell remoting

Using PowerShell remoting, the malware executes commands directly on the target using Invoke-Command:

This method leverages Windows Remote Management (WinRM), providing an alternative execution channel when PsExec or WMIC are unavailable or blocked.

5.8: PowerShell WMI execution

Finally, the malware uses the PowerShell WMI class interface directly to create remote processes with the following command sequence.

This provides functionality equivalent to wmic.exe, but through a different execution path. As a result, it might succeed in environments where the WMIC binary is restricted but WMI access remains available.

Self-propagation summary

Across all techniques, the malware attempts 21 remote execution operations per target host, spanning multiple APIs, privilege levels, and execution contexts. Each method attempts to launch the payload from:

• The infected host’s SMB share: \\<self>\share$\<payload_name>
• The target host’s locally staged path: C:\Temp\<payload_name>

This redundancy is central to The Gentlemen’s propagation strategy. In secured environments where most lateral movement techniques are mitigated, a single successful execution on a single additional host is sufficient to continue the propagation.

Free space wipe

If the --wipe argument is provided, The Gentlemen ransomware performs an additional post-encryption routine to eliminate recoverable artifacts from disk.

The malware first enumerates all available volume paths on the system. For each volume, it creates a temporary file named wipefile.tmp at the root directory and determines the amount of available free space. It then writes random data to this file in 64 MB blocks until the volume is completely filled. Once the disk space has been exhausted, the temporary file is deleted.

This process effectively overwrites all unallocated disk space with random data, preventing forensic tools from recovering remnants of previously deleted files. This includes cached or temporary versions of original unencrypted data that might still reside on disk. When combined with earlier actions such as Volume Shadow Copy deletion, this behavior reduces the likelihood of data recovery without access to the threat actor’s decryption key.

Self-delete

If the --keep flag is not provided, the malware attempts to remove its executable from disk after completing encryption.

Since a running process cannot directly delete its own binary, the ransomware generates and executes a temporary batch script at <malware_path>.batwith the following contents:

The batch script introduces a short delay by sending three Internet Control Message Protocol (ICMP) echo requests to the local host, pausing execution long enough for the main malware process to terminate. After this delay, the script deletes the original ransomware executable before removing itself. This mechanism helps reduce on-disk artifacts and hinders post-incident forensic analysis by eliminating the ransomware binary from the compromised system.

Defending against The Gentlemen ransomware

Microsoft recommends the following mitigations to reduce the impact of this threat.

• Read the human-operated ransomware threat overview for advice on developing a holistic security posture to prevent ransomware, including credential hygiene and hardening recommendations. 
• Turn on cloud-delivered protection in Microsoft Defender Antivirus or the equivalent for your antivirus product to cover rapidly evolving threat actor tools and techniques. Cloud-based machine learning protections block a huge majority of new and unknown variants. 
• Turn on tamper protection features to prevent threat actors from stopping security services. In addition to tamper protection, you can also enable and configure Microsoft Defender Antivirus always-on protection in Group Policy. 
• Enable controlled folder access. Controlled folder access helps protect your valuable data from malicious apps and threats, such as ransomware. Controlled folder access works by only allowing trusted apps to access protected folders. Protected folders are specified when controlled folder access is configured. Apps that aren’t included in the trusted apps list are prevented from making any changes to files inside protected folders. 
• Run endpoint detection and response (EDR) in block mode so that Microsoft Defender for Endpoint can block malicious artifacts, even when your non-Microsoft antivirus does not detect the threat or when Microsoft Defender Antivirus is running in passive mode. EDR in block mode works behind the scenes to remediate malicious artifacts that are detected post-breach. 
• Configure investigation and remediation in full automated mode to let Microsoft Defender for Endpoint take immediate action on alerts to resolve breaches, significantly reducing alert volume. 
• Configure automatic attack disruption in Microsoft Defender XDR. Automatic attack disruption is designed to contain attacks in progress, limit the impact on an organization’s assets, and provide more time for security teams to remediate the attack fully. 
• Microsoft Defender XDR customers can turn on attack surface reduction rules to prevent several of the infection vectors of this threat. These rules, which can be configured by any user, offer significant hardening against targeted attacks. In observed attacks, Microsoft customers who had the following rules turned on could mitigate the attack in the initial stages and prevent hands-on-keyboard activity:  
  • Block executable files from running unless they meet a prevalence, age, or trusted list criterion 
  • Block process creations originating from PSExec and WMI commands if you’re managing your devices with Intune or another MDM solution. This rule is incompatible with management through Microsoft Endpoint Configuration Manager. 
  • Use advanced protection against ransomware

Microsoft Defender detections and hunting guidance

Microsoft Defender customers can refer to the list of applicable detections below. Microsoft Defender coordinates detection, prevention, investigation, and response across endpoints, identities, email, apps to provide integrated protection against attacks like the threat discussed in this blog.

Microsoft Defender Antivirus

Microsoft Defender Antivirus detects threat components as the following malware:

• Ransom:Win64/Gentlemen

Microsoft Defender for Endpoint

The following alerts might indicate threat activity associated with this threat. These alerts, however, can be triggered by unrelated threat activity and are not monitored in the status cards provided with this report.

• Ransomware-linked threat actor detected
• Ransomware behavior detected in the file system
• Possible ransomware activity
• File backups were deleted
• Potential human-operated malicious activity
• Possible data exfiltration
• Suspicious wallpaper change

The following alerts might indicate threat activity associated with The Gentlemen ransomware if Defender for Endpoint is set to block mode.

• ‘Gentlemen’ ransomware was detected
• ‘Gentlemen’ ransomware was prevented

Microsoft Defender for Cloud Apps

The following alert might indicate threat activity associated with this threat. This alert, however, can be triggered by unrelated threat activity and are not monitored in the status cards provided with this report.

• Ransomware activity

Microsoft Security Copilot

Microsoft Security Copilot is embedded in Microsoft Defender and provides security teams with AI-powered capabilities to summarize incidents, analyze files and scripts, summarize identities, use guided responses, and generate device summaries, hunting queries, and incident reports.

Customers can also deploy AI agents, including the following Microsoft Security Copilot agents, to perform security tasks efficiently:

• Threat Intelligence Briefing agent
• Phishing Triage agent
• Threat Hunting agent
• Dynamic Threat Detection agent

Security Copilot is also available as a standalone experience where customers can perform specific security-related tasks, such as incident investigation, user analysis, and vulnerability impact assessment. In addition, Security Copilot offers developer scenarios that allow customers to build, test, publish, and integrate AI agents and plugins to meet unique security needs.

Threat intelligence reports

Microsoft Defender XDR customers can use the following threat analytics reports in the Defender portal (requires license for at least one Defender XDR product) to get the most up-to-date information about the threat actor, malicious activity, and techniques discussed in this blog. These reports provide the intelligence, protection information, and recommended actions to prevent, mitigate, or respond to associated threats found in customer environments.

Microsoft Defender XDR threat analytics

• Tool profile: Gentlemen ransomware
• Threat overview profile: Human-operated ransomware

Microsoft Security Copilot customers can also use the Microsoft Security Copilot integration in Microsoft Defender Threat Intelligence, either in the Security Copilot standalone portal or in the embedded experience in the Microsoft Defender portal to get more information about this threat actor.

Hunting queries

Microsoft Defender XDR

Microsoft Defender XDR customers can run the following advanced hunting queries to find related activity in their networks:

Known The Gentlemen ransomware files

Search for the file hashes associated with The Gentlemen ransomware activity identified in this report. 

let fileHashes = dynamic(["22b38dad7da097ea03aa28d0614164cd25fafeb1383dbc15047e34c8050f6f67"]);
union
(
   DeviceFileEvents
   | where SHA256 in (fileHashes)
   | project Timestamp, DeviceId, DeviceName, FileName, InitiatingProcessFileName, FileHash = SHA256, SourceTable = "DeviceFileEvents"
),
(
   DeviceEvents
   | where SHA256 in (fileHashes)
   | project Timestamp, DeviceId, DeviceName, FileName, InitiatingProcessFileName, FileHash = 
SHA256, SourceTable = "DeviceEvents"
),
(
   DeviceImageLoadEvents
   | where SHA256 in (fileHashes)
   | project Timestamp, DeviceId, DeviceName, FileName, InitiatingProcessFileName, FileHash = SHA256, SourceTable = "DeviceImageLoadEvents"
),
(
   DeviceProcessEvents
   | where SHA256 in (fileHashes)
   | project Timestamp, DeviceId, DeviceName, FileName, InitiatingProcessFileName, FileHash = SHA256, SourceTable = "DeviceProcessEvents"
)
| order by Timestamp desc

Microsoft Sentinel

Microsoft Sentinel customers can use the TI Mapping analytics (a series of analytics all prefixed with ‘TI map’) to automatically match the malicious domain indicators mentioned in this blog post with data in their workspace. If the TI Map analytics are not currently deployed, customers can install the Threat Intelligence solution from the Microsoft Sentinel Content Hub to have the analytics rule deployed in their Sentinel workspace.

Detect web sessions IP and file hash indicators of compromise using Advanced Security Information Model (ASIM)

The following query checks IP addresses, domains, and file hash IOCs across data sources supported by ASIM web session parser:

//IP list - _Im_WebSession
let lookback = 30d;
let ioc_ip_addr = dynamic([]);
let ioc_sha_hashes =dynamic(["22b38dad7da097ea03aa28d0614164cd25fafeb1383dbc15047e34c8050f6f67"]);
_Im_WebSession(starttime=todatetime(ago(lookback)), endtime=now())
| where DstIpAddr in (ioc_ip_addr) or FileSHA256 in (ioc_sha_hashes)
| summarize imWS_mintime=min(TimeGenerated), imWS_maxtime=max(TimeGenerated),
  EventCount=count() by SrcIpAddr, DstIpAddr, Url, Dvc, EventProduct, EventVendor

Detect files hashes indicators of compromise using ASIM

The following query checks IP addresses and file hash IOCs across data sources supported by ASIM file event parser:

// file hash list - imFileEvent
let ioc_sha_hashes = dynamic(["22b38dad7da097ea03aa28d0614164cd25fafeb1383dbc15047e34c8050f6f67"]);
imFileEvent
| where SrcFileSHA256 in (ioc_sha_hashes) or
TargetFileSHA256 in (ioc_sha_hashes)
| extend AccountName = tostring(split(User, @'')[1]), 
  AccountNTDomain = tostring(split(User, @'')[0])
| extend AlgorithmType = "SHA256"

Indicators of compromise

Acknowledgements

• License to Encrypt: The “Gentlemen” Make Their Move. Cybereason (accessed 2026-02-06)
• Unmasking The Gentlemen Ransomware: Tactics, Techniques, and Procedures Revealed. TrendMicro (accessed 2026-02-06)

Learn more

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The post The Gentlemen ransomware: Dissecting a self-propagating Go encryptor appeared first on Microsoft Security Blog.

Silent Ransom Group, a long-running data extortion operation, continues to hit U.S.-based law firms by impersonating IT support and, in some cases, visiting victims in person to gain physical access to computers, the FBI said in an alert Tuesday.

The closed group, which likely operates from Russia and emerged in 2022 after Conti disbanded, has claimed responsibility for more than 100 attacks with activity surging during the past few months, according to researchers.

The FBI’s warning comes exactly one year after the agency released a previous alert about Silent Ransom Group consistently targeting law firms since mid-2023. The group doesn’t deploy encryption, but its dual use of social engineering and in-person visits for data theft is extremely rare with no known parallels across the vast cybercrime ecosystem, multiple experts told CyberScoop.

“There were probably a lot of times that this failed before it started succeeding because there’s a lot of trial-and-error involved,” said Allan Liska, field chief information security officer at Recorded Future. Whereas other ransomware groups would rather move on to other tactics or targets, “Silent Ransom Group has seen the value especially in going after law firms, and so they’re willing to put the extra effort into it,” he added. 

The data extortion group, which is also tracked as Chatty Spider, UNC3753 and Storm-0252, isn’t as prolific as more high-tempo ransomware groups. Yet, it’s having a noticeable impact due to its proven knack for attacking organizations in the legal sector.

Halcyon tracked 134 ransomware incidents against law firms and legal services during the first quarter of this year, making it the fourth-most targeted industry accounting for more than 6% of all ransomware attacks the company tracked during the period. 

Silent Ransom Group and Inc, a ransomware-as-a-service operation dating back to mid-2023, are largely responsible for that uptick, said Cynthia Kaiser, senior vice president at Halycon’s Ransomware Research Center.

“Silent was the first group to really just be targeting law firms, and they’ve targeted major law firms” with a clear understanding of what’s most problematic for organizations in that segment, she added. “The theft of data in and of itself is the biggest issue for the law firms, so they’re tailoring a lot of their operations around what they know about the sector.”

Law firms are a rich target because data theft creates huge privilege and reputational problems, which creates the perception they might be more willing to pay high extortion demands, Kaiser said.

Silent Ransom Group’s social engineering scheme involves phone calls or phishing emails that urge employees to call one of the group’s associates posing as IT support, the FBI said. If the group’s attempt to gain access to the employee’s computer via remote access tools fails, it sends an associate to the victim’s location to physically attach a storage device to the victim’s workstation. 

This extra step is unique and places Silent Ransom Group in a completely different mode of operation than its peers in ransomware and data theft extortion. Some aggressive data theft extortion groups have harassed and threatened executives and employees with physical violence, but in-person visits for data theft are extraordinary.

“While Flashpoint has observed threat actors soliciting or co-opting both witting and unwitting insiders, we have not observed them physically sending attackers to victim locations. This tactic carries significant risk, as threat actors are able to use technology to obscure their real-world identities,” said Ian Gray, vice president of cyber threat intelligence operations at Flashpoint. 

Joe Slowik, director of cybersecurity alerting strategy at Dataminr, said it’s easy to question why potential victims would fall for this tactic. “However, humans in the workplace need to implicitly trust others to get their jobs done,” he said. 

“Questioning everything, while seemingly desirable, introduces significant friction and distrust in workplace environments and limits productivity in arbitrary ways,” Slowik added. “Criminal entities will continue to prey on human weaknesses and dependencies for success, and placing the burden solely on employees to defend against this is unfair and unreasonable.”

The FBI did not provide details about the people Silent Ransom Group uses to initiate the fake IT support calls or visit victims in person. Yet, with the group’s operators based in Russia, researchers speculate gig workers or subcontractors are playing a critical role by placing voice-based phishing calls in a common language and visiting victims at their workplace. 

Liska said he’s under the impression the group is using freelance taskers that don’t necessarily know they are committing a crime. “They may be suspicious, but you know, they need the money,” he said. 

“It’s kind of like a Doordash person that delivers Arby’s,” Liska said. “You know you’re doing really bad things to people, but you know what, they’re paying you to deliver.”

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European authorities took down a prominent virtual private network service and arrested the alleged administrator behind an operation that cybercriminals used to steal data, commit fraud and ransomware attacks, Europol said Thursday. 

First VPN, which was promoted on Russian-speaking cybercrime forums, gained popularity for providing services that allowed users to hide their infrastructure and identities. Officials said the service was entrenched in the cybercrime world and appeared in almost every major recent cybercrime investigation aided by Europol.

“For years, cybercriminals saw this VPN service as a gateway to anonymity,” Edvardas Šileris, head of Europol’s European Cybercrime Centre, said in a statement. 

“They believed it would keep them beyond the reach of law enforcement,” Šileris added. “This operation proves them wrong. Taking it offline removes a critical layer of protection that criminals depended on to operate, communicate and evade law enforcement.”

The operation stretched over two days earlier this week, led by France and the Netherlands, with support from Europol, Eurojust and eight additional countries. 

Authorities said they arrested the alleged administrator and searched their residence in Ukraine, but declined to name the person. Officials also dismantled 33 servers linked to the service and seized multiple domains, including 1vpns.com, 1vpns.net and 1vpns.org.

Investigators obtained First VPN’s user database and identified VPN connections used by alleged cybercriminals. Intelligence gathered during the operation uncovered thousands of users linked to cybercrime and formed additional leads connected to ransomware attacks and fraud schemes, officials said. 

Europol said First VPN’s users were notified of the shutdown and warned that their identities are now known to authorities. 

French and Dutch authorities started investigating First VPN in earnest in November 2023 and shared evidence with 16 countries to coordinate data analysis and support other ongoing investigations. Officials across multiple jurisdictions are using intelligence gathered during the operation to aid 21 additional inquiries globally.

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The first quarter of 2026 reinforced that attackers are moving faster, operating with greater coordination, and exploiting weaknesses before most organizations can respond effectively. From escalating geopolitical tensions to increasingly aggressive ransomware operations, the latest quarterly Threat Landscape Report highlights a security environment where reactive defense strategies are becoming unsustainable.

Quarterly Threat Landscape Report findings

Exploits unseat social engineering for top initial access vector (IAV)

One of the biggest takeaways is that vulnerability exploitation surpassed social engineering as the largest initial access vector with 38% of the total. This would be interesting on its own, but when coupled with more than 50% of all exploited vulnerabilities actively being zero-click, network facing vulnerabilities, it indicates that, at least in the short term, attackers are finding AI-enabled vulnerability exploitation easier to accomplish than exploiting human behavior. These types of vulnerabilities require no authentication and no user interaction, giving attackers rapid pathways into exposed systems and edge infrastructure. At the same time, exploitation activity was frequently preceded by large spikes in public discussion across forums, blogs, and social media platforms, demonstrating how quickly threat actors operationalize publicly available information once vulnerabilities gain visibility.

Geopolitics and FBI takedowns in the threat landscape

Geopolitical instability also continued to shape cyber operations throughout the quarter, particularly in the Middle East, where cyber activity was increasingly synchronized with military escalation. Iranian state-aligned groups targeted government infrastructure, financial services, and industrial systems, while Russian and Chinese campaigns focused heavily on intelligence collection, telecommunications infrastructure, and persistent access operations designed to remain undetected over long periods of time. The result is a threat landscape where organizations must prepare not only for immediate disruption, but also for long-term persistence inside enterprise environments.

Meanwhile, law enforcement operations targeting underground criminal infrastructure disrupted several major ransomware and credential marketplaces during Q1, including the seizure of RAMP and LeakBase. These takedowns have created operational pressure for cybercriminal groups, pushing threat actors toward smaller, decentralized communities and increasing internal distrust.

A marked shift towards "pure extortion"

The report also highlights the continued evolution of ransomware operations, particularly the growing shift toward “pure extortion” tactics focused on rapid data theft rather than traditional encryption-based attacks. Threat actors increasingly leveraged zero-click vulnerabilities to gain initial access, exfiltrate sensitive data, and pressure victims without deploying ransomware payloads that create additional operational risk and visibility.

Taken together, the findings from Q1 2026 show that organizations can no longer rely on periodic assessments and reactive workflows alone. Security teams need continuous visibility into their attack surface, better prioritization around exploitable risk, and the ability to move at a pace that matches modern attackers before small exposures become large-scale incidents.

Download the full report here.

Attackers couldn’t get enough of the vulnerabilities at their disposal last year, making exploits the top initial access vector across more than 22,000 breaches Verizon analyzed in its latest Data Breach Investigations Report released Tuesday.

The massive annual study uncovered a surge of exploited vulnerabilities during a one-year period ending in October 2025. Exploited defects accounted for 31% of all known initial access vectors, jumping from 20% the previous year. 

The uptick in exploited vulnerabilities is a reflection of the “sisyphean cause” of vulnerability management, researchers wrote in the report. “Put quite simply, there are often too many vulnerabilities and not enough time for patching all of them.”

Organizations are struggling to keep up with the torrent of vulnerabilities affecting technology across their systems. This slide is especially worrisome, and declining, among defects in the Cybersecurity and Infrastructure Security Agency’s known exploited vulnerabilities catalog.

Only 26% of the critical vulnerabilities in CISA’s catalog were fully remediated by more than 13,000 organizations Verizon studied in 2025, marking a drop from 38% the year prior. 

“There is also a worse result for the median time elapsed for a vulnerability to be fully patched by detection,” researchers wrote in the report. “Our new median time is 43 days, almost two weeks longer than last year’s 32 days.”

Verizon also noted that the median number of KEV vulnerabilities that organizations had to patch jumped from 11 in 2024 to 16 in 2025.

CISA’s KEV catalog contained more than 1,500 CVEs as of February, and 65% of those were exploited during the previous year, according to the report.

Verizon identified the five most common weaknesses of CISA KEV CVEs in its report as out-of-bounds read, heap-based buffer overflow, use after free, external control of file name or path and access of resource using incompatible type.

Attacker motivations remained relatively consistent last year, with financially-motivated cybercriminals accounting for 88% of all breaches. Espionage-driven attacks from state-affiliated groups made up the remainder.

“Ransomware continues to be among the most disruptive and impactful types of breaches we see. Not unlike the price of everything from fast food to adult beverages in ballparks, it continues to trend upward,” researchers wrote in the report.

Ransomware accounted for 48% of all breaches last year, up from 44% in 2024. Yet, Verizon observed some positive trends in ransomware as well.

Ransom payments continued to decline, with 69% of victims reporting they didn’t pay, and the median payment slid from $150,000 in 2024 to almost $140,000 last year.

Tracking ransomware remains a challenge for researchers and authorities. 

“There is a growing disconnect between what is being reported and the reality of what has occurred, in no small part due to threat actors reusing old breaches, reposting breaches from other criminal partners and making up breaches out of whole cloth to help increase their notoriety in the criminal world,” Verizon wrote in the report. “We’re beginning to think that these cybercriminals might not be entirely trustworthy.”

Yet, despite the lack of indisputable data on ransomware activity, researchers concluded: “Ransomware is still the yoga pants of cybersecurity — ubiquitous, stubbornly popular and appearing in unexpected places near you.”

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Microsoft seized infrastructure and disrupted a cybercrime service that created and sold more than 1,000 code-signing certificates that other cybercriminals used to make malware-riddled software appear trusted and legitimate for follow-on cyberattacks, including ransomware, the company said Tuesday.

The financially-motivated threat group, which Microsoft tracks as Fox Tempest, provided the malware-signing-as-a-service to multiple ransomware groups, including Rhysida, Vanilla Tempest, Storm-0501, Storm-2561 and Storm-0249 for at least a year before Microsoft was granted a court order to dismantle the operation. 

Fox Tempest, which Microsoft has been tracking since September 2025, abused Microsoft’s Artifact Signing system by fabricating identities and impersonating legitimate organizations to access the code-signing services of Microsoft, Steven Masada, assistant general counsel at Microsoft Digital Crimes Unit, said during a media briefing Monday.  

Cybercriminals paid Fox Tempest up to $9,500 to get their malicious code signed, allowing them to slip software through defenses and bypass controls designed to confirm programs are authentic and linked to a trusted source. 

“This isn’t the obvious knockoff you might find on a street corner. It’s more like a counterfeit product that’s so precise that even the experts have trouble distinguishing it from the real thing,” Masada said. “It acts as a fake ID that lets cybercriminals get into systems by walking right through the front door.”

While attackers and defenders have historically focused on the entry points of attacks, Fox Tempest’s operation exemplifies a broader move upstream to how attacks are built in the first place, he added. 

“It’s no longer just about tricking users to click on a link, it’s about exploiting the very systems that we rely on to decide what is and what isn’t safe,” Masada said. 

Cybercriminals have been reselling code-signing certificates for a least a decade, but Fox Tempest’s operation was unique in providing a massively scalable service for extortion, phishing, SEO poisoning or malware-laced advertising, said Maurice Mason, who led the investigation into Fox Tempest as principal cybercrime investigator at Microsoft’s DCU. 

Mason said ransomware operators and other threat groups primarily deployed these fraudulent certificates in ads or SEO poisoning, which brought their malicious software and infostealers to the top of search rankings, ensnaring unsuspecting victims who thought they were downloading and running legitimate applications. 

Fox Tempest’s operation, which included an authenticated portal and a drag-and-drop feature that allowed customers to get their code signed, was directly linked to the deployment of dozens of malware families, including Oyster, Lumma Stealer, MuddyWater and Vidar, he added. 

Microsoft said the threat group is also linked to ransomware affiliates for INC, Qilin, Akira and others. The operation had a global impact, resulting in attacks on the healthcare, education, government and financial services sectors, and most heavily targeted organizations and people in the United States, France, India and China.

“Why wouldn’t you pay those thousands of dollars if you’re a threat actor and you’re getting it back in extortion and ransomware worth millions? This is like chump change to you,” Mason said. 

Microsoft said it evicted or deleted more than 1,000 accounts and subscriptions Fox Tempest used to provide its services. The company also seized the threat group’s website, took hundreds of virtual machines offline and blocked access to a site hosting the underlying code. 

“This disruption likely is going to raise the cost for attackers, and we’re hoping that they move off of using these services,” Mason said. “Obviously it’s just a disruption and there’s other things that they’ll probably move to, or someone might try to do this a different way next time.”

Fox Tempest is an example of the fully developed cybercrime economy defenders confront now, Masada said. 

“In many cases, an actor no longer needs to build an attack from scratch. They can simply assemble one by purchasing its components — a phish kit from one vendor, malware from another, infrastructure and optimization tools from yet others, and so on,” he said. 

“As we focus more of our recent disruptions on marketplaces and service providers, we’re getting a much clearer picture of how the economy actually functions, and what’s emerging is a stratified ecosystem,” Masada added. 

“At one end, you have commoditized tools that are mass produced and built for scale, things like turnkey phishing kits or credential harvesting services,” he said. “But above that, we’re seeing a more sophisticated tier of operators, highly specialized services focused on evasion, durability, and optimization. These are not just enabling attacks, they’re engineering them to succeed against modern defenses.”

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Fox Tempest is a financially motivated threat actor that operates a malware-signing-as-a-service (MSaaS)  used by other cybercriminals to more effectively distribute malicious code, including ransomware. The threat actor abuses Microsoft Artifact Signing to generate short-lived, fraudulent code-signing certificates to appear legitimately signed, allowing malware to evade security controls.

Fox Tempest has created over a thousand certificates and established hundreds of Azure tenants and subscriptions to support its operations. Microsoft has revoked over one thousand code signing certificates attributed to Fox Tempest. In May 2026, Microsoft’s Digital Crimes Unit (DCU), with support from industry partner Resecurity, disrupted Fox Tempest’s MSaaS offering, targeting the infrastructure and access model that enables its broader criminal use.

Microsoft Threat Intelligence observed Fox Tempest’s operations enabling the deployment of Rhysida ransomware by threat actors such as Vanilla Tempest, as well as the distribution of other malware families including Oyster, Lumma Stealer, and Vidar. The consistency, scale, and downstream impact of the resulting attack activity demonstrate that Fox Tempest is a vital operator within the broader cybercrime ecosystem.

In this blog, we examine how Fox Tempest’s MSaaS operation functioned and how it enabled the delivery of trusted, signed malware across the cybercrime ecosystem. We also provide Microsoft Defender detections, indicators of compromise (IOCs), and mitigation recommendations to help organizations identify and disrupt similar activity.

Fox Tempest’s role and impact

Fox Tempest doesn’t directly target victims but instead provides supporting services that enable ransomware operations by other threat actors. Microsoft Threat Intelligence has tracked Fox Tempest since September 2025. Microsoft Threat Intelligence has linked the actor to various ransomware groups including Vanilla Tempest, Storm-0501, Storm-2561, and Storm-0249, who have all leveraged Fox Tempest-signed malware in active intrusions. Malware delivery in these attacks have included use of legitimate purchased advertisements, malvertising, and SEO poisoning.

Cryptocurrency analysis associated with Fox Tempest has identified clear links tying the actor to ransomware affiliates responsible for delivering several prominent ransomware families, including INC, Qilin, Akira, and others, with observed proceeds in the millions. Based on the scale of the MSaaS offering, Microsoft Threat Intelligence assesses that Fox Tempest is a well-resourced group handling infrastructure creation, customer relations, and financial transactions.

The downstream impact of these operations has resulted in attacks against a broad range of industry sectors, including healthcare, education, government, and financial services, impacting organizations globally including, but not limited to the United States, France, India, and China.

Fox Tempest’s malware signing as a service infrastructure

Fox Tempest’s MSaaS capability was available through the website signspace[.]cloud, a now defunct service that was disrupted by DCU, which enabled other threat actors to fraudulently obtain short-lived Microsoft-issued certificates that were valid for only 72 hours, obtained through Artifact Signing (previously named Azure Trusted Signing). This use of short-life certificates from a trusted source allowed malware and ransomware to masquerade as legitimate software (like AnyDesk, Teams, Putty, and Webex) to bypass security controls, significantly increasing the likelihood of execution and successful delivery. Fox Tempest offered this MSaaS capability to the ransomware ecosystem since at least May 2025.

To obtain legitimate signed certificates through Artifact Signing, the requestor must pass detailed identify validation processes in keeping with industry standard verifiable credentials (VC), which suggests the threat actor very likely used stolen identities based in the United States and Canada to masquerade as a legitimate entity and obtain the necessary digital credentials for signing. The SignSpace website was built on Artifact Signing and enabled secure file signing through an admin panel and user page, leveraging Azure subscriptions, certificates, and a structured database for managing users and files. A GitHub repository, called code‑signing‑service, included configuration files and technical details that directly linked it to the infrastructure behind signspace[.]cloud.

The signspace[.]cloud service has two unique modeling groupings: the admin and the customers. The admin is responsible for maintaining the tooling, account creation, and infrastructure, while the customers provide files to be fraudulently code signed. Customers who accessed the service could upload malicious files to be signed using Fox Tempest-controlled certificates.

Below are examples of the signspace[.]cloud portal as seen by Fox Tempest’s customers:

In February 2026, Microsoft Threat Intelligence observed a notable shift in Fox Tempest’s operational infrastructure. Fox Tempest transitioned to providing customers with pre-configured virtual machines (VMs) hosted on US-based virtual private server provider Cloudzy’s infrastructure, allowing threat actors to upload their malicious files directly to Fox Tempest‑controlled environments and receive signed binaries in return. This infrastructure evolution reduced friction for customers, improved operational security for Fox Tempest, and further streamlined the delivery of malicious but trusted, signed malware at scale. Microsoft’s Digital Crimes Unit (DCU) disrupted this infrastructure and continues to partner with Cloudzy to identify and disrupt related infrastructure.

Below is an example of the Fox Tempest-provided VM environment as seen by customers:

Inside the VM, Fox Tempest provided files that are used to sign code:

• The first file, metadata.json, was a configuration file that pointed to an Azure‑hosted endpoint which also included the signing account and certificate profile.
• The second file, test.js, is an example of a file provided by Fox Tempest that had been digitally signed to demonstrate their signing capabilities to customers.
• The third file, PS code sample.txt, contains the PowerShell script they used to sign customer‑submitted files using certificates under Fox Tempest control.

Threat actors using Fox Tempest’s MSaaS offering paid thousands of dollars to get their malicious code signed, as shown below with the Google Form detailing the service’s pricing model. Actors filled out the form before being added to a queue to submit payment and gain access to a VM. The form (written in both English and Russian) asks the user to choose a selected plan from a price list of $5000 USD, $7500 USD, or $9000 USD, with a mention that higher paying plans receive priority in the queue sequence.

Fox Tempest engaged directly with customers using a Telegram channel, EV Certs for Sale by SamCodeSign under the user account arbadakarba2000. All signing activity occurred using a Fox Tempest-provided email address associated with a very small number of IP addresses.

Case study: Fox Tempest enables Vanilla Tempest attacks

Vanilla Tempest began using Fox Tempest’s MSaaS service as early as June 2025. Through this service, Vanilla Tempest uploaded malicious payloads such as trojanized Microsoft Teams installers, which Fox Tempest would fraudulently signed to appear legitimate. Vanilla Tempest would then distribute these signed binaries through legitimately purchased advertisements that redirected users searching for Microsoft Teams to attacker‑controlled advertisements and fraudulent download pages.

Victims were presented with a malicious MSTeamsSetup.exe in place of the legitimate client, reflecting a broader pattern of Vanilla Tempest frequently abusing trusted software brands to lure victims and establish initial access. Execution of the counterfeit installer resulted in the deployment of the Oyster backdoor (also known as Broomstick), a modular, multistage implant that establishes persistent remote access, initiates command‑and‑control (C2) communications, collects host‑level information, and enables the delivery of additional payloads. By masquerading as a widely deployed enterprise collaboration tool hiding behind a fraudulently signed binary, Vanilla Tempest’s Oyster payload was likely able to evade casual detection and blend into normal enterprise activity. In some observed cases, Vanilla Tempest also deployed Rhysida ransomware within victim environments using the same process.

Defending against Fox Tempest-enabled attacks

To defend against Fox Tempest tactics, techniques, and procedures (TTPs) and similar activity, Microsoft recommends the following mitigation measures:

• Read the human-operated ransomware threat overview for advice on developing a holistic security posture to prevent ransomware, including credential hygiene and hardening recommendations.
• Turn on cloud-delivered protection in Microsoft Defender Antivirus or the equivalent for your antivirus product to cover rapidly evolving attacker tools and techniques. Cloud-based machine learning protections block a huge majority of new and unknown variants.
• Turn on Safe Links and Safe Attachments in Microsoft Defender for Office 365.
• Encourage users to use Microsoft Edge and other web browsers that support Microsoft Defender SmartScreen, which identifies and blocks malicious websites, including phishing sites, scam sites, and sites that host malware.
• Turn on tenant-wide tamper protection features to prevent attackers from stopping security services or using antivirus exclusions. Without tamper protection, attackers could simply turn off Microsoft Defender Antivirus without the need to acquire higher privileges.
  • Customers running Intune or Microsoft Defender for Endpoint Security Configuration can enable DisableLocalAdminMerge to prevent modification of antivirus exclusions via GPO. 
  • In addition to tamper protection, you can also enable and configure Microsoft Defender Antivirus always-on protection in Group Policy.
  • If there is an issue with a device during roll out of various antivirus features, the device can be placed in troubleshooting mode to turn off tamper protection temporarily without impacting the wider organizational security policy.
• Microsoft Defender XDR customers can turn on attack surface reduction rules to prevent several of the infection vectors of this threat. These rules, which can be configured by any user, offer significant hardening against targeted attacks. In observed attacks, Microsoft customers who had the following rules turned on could mitigate the attack in the initial stages and prevent hands-on-keyboard activity:
  • Use advanced protection against ransomware

Microsoft Defender detections

Microsoft Defender customers can refer to the list of applicable detections below. Microsoft Defender coordinates detection, prevention, investigation, and response across endpoints, identities, email, apps to provide integrated protection against attacks like the threat discussed in this blog.

Microsoft Security Copilot

Microsoft Security Copilot is embedded in Microsoft Defender and provides security teams with AI-powered capabilities to summarize incidents, analyze files and scripts, summarize identities, use guided responses, and generate device summaries, hunting queries, and incident reports.

Customers can also deploy AI agents, including the following Microsoft Security Copilot agents, to perform security tasks efficiently:

• Threat Intelligence Briefing agent
• Phishing Triage agent
• Threat Hunting agent
• Dynamic Threat Detection agent

Security Copilot is also available as a standalone experience where customers can perform specific security-related tasks, such as incident investigation, user analysis, and vulnerability impact assessment. In addition, Security Copilot offers developer scenarios that allow customers to build, test, publish, and integrate AI agents and plugins to meet unique security needs.

Threat intelligence reports

Microsoft Defender XDR customers can use the following threat analytics reports in the Defender portal (requires license for at least one Defender XDR product) to get the most up-to-date information about the threat actor, malicious activity, and techniques discussed in this blog. These reports provide the intelligence, protection information, and recommended actions to prevent, mitigate, or respond to associated threats found in customer environments.

Microsoft Defender XDR threat analytics

• Actor profile: Fox Tempest
• Actor profile: Vanilla Tempest
• Threat Overview profile: Human-operated ransomware
• Activity profile: Vanilla Tempest leverages fake Microsoft Teams setup to deliver Oyster backdoor

Microsoft Security Copilot customers can also use the Microsoft Security Copilot integration in Microsoft Defender Threat Intelligence, either in the Security Copilot standalone portal or in the embedded experience in the Microsoft Defender portal to get more information about this threat actor.

Indicators of compromise

Learn more

For the latest security research from the Microsoft Threat Intelligence community, check out the Microsoft Threat Intelligence Blog.

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