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.”

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Researchers and threat hunters are scrambling to respond to an actively exploited authentication-bypass vulnerability affecting Palo Alto Networks customers’ firewalls. 

The company initially tagged CVE-2026-0257 with a medium-severity rating when it disclosed the defect May 13, but quickly reassessed it as critical after Rapid7 observed and confirmed active exploitation in the wild. The Cybersecurity and Infrastructure Security Agency followed suit, and added the vulnerability to its known exploited vulnerabilities catalog Friday.

The escalated threat posed by the defect, which allows remote attackers to bypass security restrictions and establish a VPN connection to an affected firewall, showcases how quickly a seemingly mild vulnerability can turn into an urgent warning. 

“Palo Alto Networks is actively monitoring limited exploitation attempts targeting CVE-2026-0257 on unpatched PAN-OS devices where mitigations have not been applied,” a company spokesperson said in a statement. The company on Friday urged all customers to immediately apply the patch or follow its recommended steps for mitigation. 

The vendor and Rapid7, which first observed exploitation May 17 in a customer environment, declined to say how many organizations are impacted thus far. Yet, Douglas McKee, director of vulnerability intelligence at Rapid7, warned: “We’ve continued to see new victims roll in, including a couple of customers hit within just an hour of each other during a second wave of activity” on May 21. 

Jake Knott, security researcher at watchTowr, told CyberScoop the vulnerability and resulting exploits follows a recurring trend wherein attackers target exposed network edge devices and rapidly identify, develop and weaponize exploits for initial access. 

“This is yet another authentication bypass on a device whose sole job is to guard the front door to an organization’s network,” he said. “What stands out is how simple it is — an attacker can forge a valid authentication cookie using nothing more than the appliance’s publicly available TLS certificate. The entire exploit is a single HTTP request.”

The vulnerability has a few requisites that limit exposure, specifically posing risk to some Palo Alto Networks customers running GlobalProtect portal or gateway configured to enable authentication override cookies. 

“The cookie encryption and decryption certificate must be reused with another feature, which potentially exposes the public key for that certificate,” said Caitlin Condon, vice president of security research at VulnCheck.

“It’s difficult to say how many deployments meet those criteria for exploitability, but Palo Alto Networks firewalls have a very large footprint, which means even uncommon configurations can present significant attack surface area,” she added.

Rapid7 said the same attacker or group is likely responsible for both waves of exploitation last month, but in many cases attackers are not establishing a full VPN connection or moving to other parts of the impacted network. 

The attackers are “highly opportunistic and clearly monitor the security research community,” McKee said. “Attackers are purposefully weaponizing medium-severity vulnerabilities, which are typically lower priority or blind spots for organizations.”

Multiple threat clusters are swarming to the opportunity and quickly adapting to published research.  Researchers have not attributed the malicious activity to any specific threat groups. 

“Their exact origins and long-term objectives remain unclear, as they currently seem focused purely on opportunistic initial access rather than targeted, long-term espionage,” McKee said. 

Palo Alto Networks said it discovered the vulnerability internally through its use of frontier AI tools. Yet, within days of its public disclosure, initial assessments were proven inadequate.

“This is a pattern we continue to see — the urgency only arrives after exploitation is underway,” Knott said. “Organizations that wait for confirmation of active exploitation before patching will consistently find themselves reacting too late.”

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Two of the most advanced artificial intelligence models — Anthropic’s Claude Mythos Preview and OpenAI’s GPT-5.5 — have significantly surpassed the already-accelerating pace at which AI systems are completing autonomous cybersecurity tasks, according to separate findings published Wednesday by the United Kingdom’s AI Security Institute (AISI) and Palo Alto Networks.

The AISI, which conducts pre-deployment evaluations of frontier AI models on behalf of the British government, said both Claude Mythos Preview and GPT-5.5 have substantially exceeded the doubling trend the institute had been tracking since late 2024. Whether the results represent an isolated capability jump or the start of a new, faster trajectory remains unclear.

The AISI estimated earlier this year that frontier models’ 80% reliability cyber time horizon — a measure of how long a task takes a human expert, used as a proxy for AI autonomy — had been doubling approximately every five months. That was itself roughly half the eight-month doubling time the institute estimated in November 2025. Now Mythos Preview and GPT-5.5 have since outperformed any trend lines the institute has measured.

“Frontier AI’s autonomous cyber and software capability is advancing quickly: the length of cyber tasks that frontier models can complete autonomously has doubled on the order of months, not years,” the AISI wrote.

The clearest evidence of the capability jump came from the AISI’s cyber ranges, its structured simulations of multi-stage attacks against small, undefended enterprise networks. A newer checkpoint of Claude Mythos Preview became the first model to complete both of the institute’s ranges. It solved “The Last Ones,” a 32-step simulated corporate network attack, in 6 of 10 attempts, and completed “Cooling Tower” — previously unsolved by any model — in 3 of 10 attempts. GPT-5.5 solved “The Last Ones” in 3 of 10 attempts.

Palo Alto Networks reached similar conclusions through its own testing. The company said it began testing Claude Mythos in April as a launch partner for Anthropic’s Project Glasswing, and has since tested Claude Opus 4.7 and OpenAI’s GPT-5.5-Cyber as part of OpenAI‘s Trusted Access for Cyber program.

“The latest models are extraordinarily capable at finding vulnerabilities and changing them into critical exploit paths in near-real-time,” Palo Alto Networks wrote.

The company released security advisories covering 26 CVEs representing 75 issues — compared to a typical monthly volume of fewer than five CVEs — that were identified through AI model scanning across more than 130 products. All important vulnerabilities in its SaaS products had been patched, with patches available for all customer-operated products.

The AISI was careful to note the limits of its data. The estimates are based on a relatively small number of models, and the hardest tasks in the test suite have the least amount of human comparison data. Even so, the institute said the overall trend holds up: dropping any single model from the analysis barely moves the needle, shifting the estimated doubling time by less than a month in either direction. Separate research from METR, a nonprofit that tracks how quickly AI handles software tasks, arrived at a nearly identical figure — a doubling time of approximately four months since late 2024.

“No single benchmark result should be read as a precise measure of AI capability,” the AISI wrote. “Regardless, the direction of change and rapid growth have been consistent across the models, methodological choices and independent data we examined.”

Palo Alto Networks outlined four immediate priorities for enterprises as these models continue to grow in usage: First, find and fix vulnerabilities in code and applications before attackers do. Second, shrink the attack surface and use AI to spot security misconfigurations. Third, deploy detection and response tools across all systems, using machine learning to catch threats in real time. Fourth, build security operations fast enough to respond in minutes, because AI-powered attacks may soon unfold that quickly.

The AISI said it is developing more demanding evaluations, including new cyber ranges and the addition of active cyber defenses, to better reflect real-world conditions as model capabilities continue to advance.

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Attackers are actively exploiting a zero-day vulnerability affecting some Palo Alto Networks’ customers’ firewalls, the security vendor said in an advisory Tuesday.

The critical memory corruption vulnerability — CVE-2026-0300 — affects the authentication portal of PAN-OS, and allows unauthenticated attackers to run  code with root privileges on the vendor’s PA-Series and VM-Series firewalls, the company said.

Palo Alto Networks did not say when or how it became aware of active exploitation, nor when the earliest known exploitation occurred. The Cybersecurity and Infrastructure Security Agency added the defect to its known exploited vulnerabilities catalog Wednesday.

The company hasn’t released a patch for the vulnerability or described the scope and objective of confirmed attacks.

“This vulnerability is specific to a limited number of customers with their User-ID Authentication Portal (Captive Portal) exposed to the public internet or untrusted IP addresses. We have observed limited exploitation of this issue and are working to release software fixes, with the first updates expected to be available on May 13,” a Palo Alto Networks spokesperson told CyberScoop.

The company said firewalls exposed to the buffer-overflow vulnerability, which has a CVSS rating of 9.3, are broadly exposed in real-world deployments, and it described the attack complexity as low.

Shadowserver scans found more than 5,800 publicly exposed VM-Series firewalls running PAN-OS as of Tuesday, yet it’s unknown how many of those instances have restricted authentication access to trusted internal IP addresses or disabled the feature altogether.

“We have provided clear mitigation guidance to our customers to secure their environments immediately. This issue does not impact Cloud NGFW or Panorama appliances. We remain committed to a transparent, security-first approach to protect our global customer base,” Palo Alto Networks’ spokesperson added.

Benjamin Harris, CEO and founder of watchTowr, noted that Palo Alto Networks proactively alerted customers to the zero-day, a step that allowed defenders to take action on potentially exposed instances. 

“In a bad situation, that is the best they can do immediately. However, that also alerts everyone to the existence of a vulnerability,” he told CyberScoop.

Despite the risk, Harris said watchTowr expects attacks linked to the zero-day exploit to be “very limited.” 

Palo Alto Networks and its impacted customers remain the only parties to have observed exploitation in the wild, but researchers warn that will likely change soon. 

“It’s likely rules will also start to fire in third-party organizations and honeypots shortly,” Caitlin Condon, vice president of security research at VulnCheck, told CyberScoop. 

“Management interfaces, login pages, and authentication portals have been common adversary targets for both opportunistic and targeted campaigns in recent years,” she added. “With researcher and community eyes on the vulnerability, it’s likely that we’ll see public exploits and broader exploitation quickly, provided the issue isn’t prohibitively difficult to exploit.”

Palo Alto Networks has yet to attribute the attacks to any known threat group, publish indicators or compromise, nor disclose the type of organizations that have been targeted and impacted. 

Researchers are hunting for malicious activity and advise customers to apply patches upon release.

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