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Network ‘background noise’ may predict the next big edge-device vulnerability

Attackers rarely exploit an edge-device vulnerability indiscriminately. Typically, they first test how widely the flaw can be used and how much access it can provide, then move on to steal data or disrupt operations.

Pre-attack surveillance and planning leaves a lot of noise in its wake. These signals — particularly spikes in traffic that are hitting specific vendors — can act as an early-warning system, often preceding public vulnerability disclosures, according to research GreyNoise shared exclusively with CyberScoop prior to its release. 

Roughly half of every activity surge GreyNoise detected during a 103-day study last winter was followed by a vulnerability disclosure from the same targeted vendor within three weeks, GreyNoise said in its report.

Researchers determined that the median warning of an impending vulnerability disclosure arrived nine days before the targeted vendor issued a public alert to its customers.

“Virtually every time we see large scale spikes in reconnaissance and inventory activity looking for a certain device, it’s because somebody knows about a vulnerability,” Andrew Morris, founder and chief architect at GreyNoise, told CyberScoop.

“Within a few days or weeks — usually within the responsible disclosure timeline — a new very bad vulnerability comes out,” he added.

GreyNoise insists that every day of advance notice matters, giving defenders an opportunity to defend against and thwart potential attacks before they occur. 

The real-time network edge scanning platform spotted 104 distinct activity surges across 18 vendors during its study period. These embedded systems, including routers, VPNs, firewalls and other security systems, consistently account for the most commonly exploited vulnerabilities.

“Attackers love hacking security devices like security appliances. The irony of that is just not lost on me at all,” Morris said.

“It hasn’t gotten bad enough for us to start taking the security of these devices seriously,” he added. “It’s not bad enough for us to take it seriously enough to start ripping these things out and replacing them with new devices or new vendors.”

GreyNoise linked traffic surges to a swarm of vulnerabilities disclosed by vendors across the market, including Cisco, Palo Alto Networks, Fortinet, Ivanti, HPE, MicroTik, TP-Link, VMware, Juniper, F5, Netgear and others.

“It’s becoming scientifically empirical, and it’s becoming more like meteorology than mysticism,” Morris said. “This is like clockwork now.”

GreyNoise breaks these traffic surges down to measure intensity and breadth. Session counts indicate how hard existing sources are hammering a specific vendor and unique source IP counts demonstrate how widely new infrastructure is joining the activity, researchers wrote in the report.

“When both the intensity and breadth of targeting increase simultaneously, it signals a coordinated escalation,” the report said. 

“When you see a session spike against one of your vendors and new source IPs joining at the same time, treat it as a high-confidence reason to look harder. When you see only an IP spike, do not assume a vulnerability is coming,” researchers added. 

The study bolsters other research from Verizon, Google Threat Intelligence Group and Mandiant — landing during what GreyNoise calls “the most aggressive period of edge device exploitation on record.”

This activity doesn’t happen in a vacuum and threat groups aren’t flooding edge devices with traffic for free or for fun, according to Morris.

“People tend to treat internet background noise like it’s this unexplainable phenomenon,” he said. “They’re clearly trying to test the existence of a vulnerability in order to compromise the systems.”

The post Network ‘background noise’ may predict the next big edge-device vulnerability appeared first on CyberScoop.

Russia Hacked Routers to Steal Microsoft Office Tokens

Hackers linked to Russia’s military intelligence units are using known flaws in older Internet routers to mass harvest authentication tokens from Microsoft Office users, security experts warned today. The spying campaign allowed state-backed Russian hackers to quietly siphon authentication tokens from users on more than 18,000 networks without deploying any malicious software or code.

Microsoft said in a blog post today it identified more than 200 organizations and 5,000 consumer devices that were caught up in a stealthy but remarkably simple spying network built by a Russia-backed threat actor known as “Forest Blizzard.”

How targeted DNS requests were redirected at the router. Image: Black Lotus Labs.

Also known as APT28 and Fancy Bear, Forest Blizzard is attributed to the military intelligence units within Russia’s General Staff Main Intelligence Directorate (GRU). APT 28 famously compromised the Hillary Clinton campaign, the Democratic National Committee, and the Democratic Congressional Campaign Committee in 2016 in an attempt to interfere with the U.S. presidential election.

Researchers at Black Lotus Labs, a security division of the Internet backbone provider Lumen, found that at the peak of its activity in December 2025, Forest Blizzard’s surveillance dragnet ensnared more than 18,000 Internet routers that were mostly unsupported, end-of-life routers, or else far behind on security updates. A new report from Lumen says the hackers primarily targeted government agencies—including ministries of foreign affairs, law enforcement, and third-party email providers.

Black Lotus Security Engineer Ryan English said the GRU hackers did not need to install malware on the targeted routers, which were mainly older Mikrotik and TP-Link devices marketed to the Small Office/Home Office (SOHO) market. Instead, they used known vulnerabilities to modify the Domain Name System (DNS) settings of the routers to include DNS servers controlled by the hackers.

As the U.K.’s National Cyber Security Centre (NCSC) notes in a new advisory detailing how Russian cyber actors have been compromising routers, DNS is what allows individuals to reach websites by typing familiar addresses, instead of associated IP addresses. In a DNS hijacking attack, bad actors interfere with this process to covertly send users to malicious websites designed to steal login details or other sensitive information.

English said the routers attacked by Forest Blizzard were reconfigured to use DNS servers that pointed to a handful of virtual private servers controlled by the attackers. Importantly, the attackers could then propagate their malicious DNS settings to all users on the local network, and from that point forward intercept any OAuth authentication tokens transmitted by those users.

DNS hijacking through router compromise. Image: Microsoft.

Because those tokens are typically transmitted only after the user has successfully logged in and gone through multi-factor authentication, the attackers could gain direct access to victim accounts without ever having to phish each user’s credentials and/or one-time codes.

“Everyone is looking for some sophisticated malware to drop something on your mobile devices or something,” English said. “These guys didn’t use malware. They did this in an old-school, graybeard way that isn’t really sexy but it gets the job done.”

Microsoft refers to the Forest Blizzard activity as using DNS hijacking “to support post-compromise adversary-in-the-middle (AiTM) attacks on Transport Layer Security (TLS) connections against Microsoft Outlook on the web domains.” The software giant said while targeting SOHO devices isn’t a new tactic, this is the first time Microsoft has seen Forest Blizzard using “DNS hijacking at scale to support AiTM of TLS connections after exploiting edge devices.”

Black Lotus Labs engineer Danny Adamitis said it will be interesting to see how Forest Blizzard reacts to today’s flurry of attention to their espionage operation, noting that the group immediately switched up its tactics in response to a similar NCSC report (PDF) in August 2025. At the time, Forest Blizzard was using malware to control a far more targeted and smaller group of compromised routers. But Adamitis said the day after the NCSC report, the group quickly ditched the malware approach in favor of mass-altering the DNS settings on thousands of vulnerable routers.

“Before the last NCSC report came out they used this capability in very limited instances,” Adamitis told KrebsOnSecurity. “After the report was released they implemented the capability in a more systemic fashion and used it to target everything that was vulnerable.”

TP-Link was among the router makers facing a complete ban in the United States. But on March 23, the U.S. Federal Communications Commission (FCC) took a much broader approach, announcing it would no longer certify consumer-grade Internet routers that are produced outside of the United States.

The FCC warned that foreign-made routers had become an untenable national security threat, and that poorly-secured routers present “a severe cybersecurity risk that could be leveraged to immediately and severely disrupt U.S. critical infrastructure and directly harm U.S. persons.”

Experts have countered that few new consumer-grade routers would be available for purchase under this new FCC policy (besides maybe Musk’s Starlink satellite Internet routers, which are produced in Texas). The FCC says router makers can apply for a special “conditional approval” from the Department of War or Department of Homeland Security, and that the new policy does not affect any previously-purchased consumer-grade routers.

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