Microsoft today pushed software updates to fix a staggering 167 security vulnerabilities in its Windows operating systems and related software, including a SharePoint Server zero-day and a publicly disclosed weakness in Windows Defender dubbed “BlueHammer.” Separately, Google Chrome fixed its fourth zero-day of 2026, and an emergency update for Adobe Reader nixes an actively exploited flaw that can lead to remote code execution.

Redmond warns that attackers are already targeting CVE-2026-32201, a vulnerability in Microsoft SharePoint Server that allows attackers to spoof trusted content or interfaces over a network.

Mike Walters, president and co-founder of Action1, said CVE-2026-32201 can be used to deceive employees, partners, or customers by presenting falsified information within trusted SharePoint environments.

“This CVE can enable phishing attacks, unauthorized data manipulation, or social engineering campaigns that lead to further compromise,” Walters said. “The presence of active exploitation significantly increases organizational risk.”

Microsoft also addressed BlueHammer (CVE-2026-33825), a privilege escalation bug in Windows Defender. According to BleepingComputer, the researcher who discovered the flaw published exploit code for it after notifying Microsoft and growing exasperated with their response. Will Dormann, senior principal vulnerability analyst at Tharros, says he confirmed that the public BlueHammer exploit code no longer works after installing today’s patches.

Satnam Narang, senior staff research engineer at Tenable, said April marks the second-biggest Patch Tuesday ever for Microsoft. Narang also said there are indications that a zero-day flaw Adobe patched in an emergency update on April 11 — CVE-2026-34621 — has seen active exploitation since at least November 2025.

Adam Barnett, lead software engineer at Rapid7, called the patch total from Microsoft today “a new record in that category” because it includes nearly 60 browser vulnerabilities. Barnett said it might be tempting to imagine that this sudden spike was tied to the buzz around the announcement a week ago today of Project Glasswing — a much-hyped but still unreleased new AI capability from Anthropic that is reportedly quite good at finding bugs in a vast array of software.

But he notes that Microsoft Edge is based on the Chromium engine, and the Chromium maintainers acknowledge a wide range of researchers for the vulnerabilities which Microsoft republished last Friday.

“A safe conclusion is that this increase in volume is driven by ever-expanding AI capabilities,” Barnett said. “We should expect to see further increases in vulnerability reporting volume as the impact of AI models extend further, both in terms of capability and availability.”

Finally, no matter what browser you use to surf the web, it’s important to completely close out and restart the browser periodically. This is really easy to put off (especially if you have a bajillion tabs open at any time) but it’s the only way to ensure that any available updates get installed. For example, a Google Chrome update released earlier this month fixed 21 security holes, including the high-severity zero-day flaw CVE-2026-5281.

For a clickable, per-patch breakdown, check out the SANS Internet Storm Center Patch Tuesday roundup. Running into problems applying any of these updates? Leave a note about it in the comments below and there’s a decent chance someone here will pipe in with a solution.

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.

A financially motivated data theft and extortion group is attempting to inject itself into the Iran war, unleashing a worm that spreads through poorly secured cloud services and wipes data on infected systems that use Iran’s time zone or have Farsi set as the default language.

Experts say the wiper campaign against Iran materialized this past weekend and came from a relatively new cybercrime group known as TeamPCP. In December 2025, the group began compromising corporate cloud environments using a self-propagating worm that went after exposed Docker APIs, Kubernetes clusters, Redis servers, and the React2Shell vulnerability. TeamPCP then attempted to move laterally through victim networks, siphoning authentication credentials and extorting victims over Telegram.

A snippet of the malicious CanisterWorm that seeks out and destroys data on systems that match Iran’s timezone or have Farsi as the default language. Image: Aikido.dev.

In a profile of TeamPCP published in January, the security firm Flare said the group weaponizes exposed control planes rather than exploiting endpoints, predominantly targeting cloud infrastructure over end-user devices, with Azure (61%) and AWS (36%) accounting for 97% of compromised servers.

“TeamPCP’s strength does not come from novel exploits or original malware, but from the large-scale automation and integration of well-known attack techniques,” Flare’s Assaf Morag wrote. “The group industrializes existing vulnerabilities, misconfigurations, and recycled tooling into a cloud-native exploitation platform that turns exposed infrastructure into a self-propagating criminal ecosystem.”

On March 19, TeamPCP executed a supply chain attack against the vulnerability scanner Trivy from Aqua Security, injecting credential-stealing malware into official releases on GitHub actions. Aqua Security said it has since removed the harmful files, but the security firm Wiz notes the attackers were able to publish malicious versions that snarfed SSH keys, cloud credentials, Kubernetes tokens and cryptocurrency wallets from users.

Over the weekend, the same technical infrastructure TeamPCP used in the Trivy attack was leveraged to deploy a new malicious payload which executes a wiper attack if the user’s timezone and locale are determined to correspond to Iran, said Charlie Eriksen, a security researcher at Aikido. In a blog post published on Sunday, Eriksen said if the wiper component detects that the victim is in Iran and has access to a Kubernetes cluster, it will destroy data on every node in that cluster.

“If it doesn’t it will just wipe the local machine,” Eriksen told KrebsOnSecurity.

Image: Aikido.dev.

Aikido refers to TeamPCP’s infrastructure as “CanisterWorm” because the group orchestrates their campaigns using an Internet Computer Protocol (ICP) canister — a system of tamperproof, blockchain-based “smart contracts” that combine both code and data. ICP canisters can serve Web content directly to visitors, and their distributed architecture makes them resistant to takedown attempts. These canisters will remain reachable so long as their operators continue to pay virtual currency fees to keep them online.

Eriksen said the people behind TeamPCP are bragging about their exploits in a group on Telegram and claim to have used the worm to steal vast amounts of sensitive data from major companies, including a large multinational pharmaceutical firm.

“When they compromised Aqua a second time, they took a lot of GitHub accounts and started spamming these with junk messages,” Eriksen said. “It was almost like they were just showing off how much access they had. Clearly, they have an entire stash of these credentials, and what we’ve seen so far is probably a small sample of what they have.”

Security experts say the spammed GitHub messages could be a way for TeamPCP to ensure that any code packages tainted with their malware will remain prominent in GitHub searches. In a newsletter published today titled GitHub is Starting to Have a Real Malware Problem, Risky Business reporter Catalin Cimpanu writes that attackers often are seen pushing meaningless commits to their repos or using online services that sell GitHub stars and “likes” to keep malicious packages at the top of the GitHub search page.

This weekend’s outbreak is the second major supply chain attack involving Trivy in as many months. At the end of February, Trivy was hit as part of an automated threat called HackerBot-Claw, which mass exploited misconfigured workflows in GitHub Actions to steal authentication tokens.

Eriksen said it appears TeamPCP used access gained in the first attack on Aqua Security to perpetrate this weekend’s mischief. But he said there is no reliable way to tell whether TeamPCP’s wiper actually succeeded in trashing any data from victim systems, and that the malicious payload was only active for a short time over the weekend.

“They’ve been taking [the malicious code] up and down, rapidly changing it adding new features,” Eriksen said, noting that when the malicious canister wasn’t serving up malware downloads it was pointing visitors to a Rick Roll video on YouTube.

“It’s a little all over the place, and there’s a chance this whole Iran thing is just their way of getting attention,” Eriksen said. “I feel like these people are really playing this Chaotic Evil role here.”

Cimpanu observed that supply chain attacks have increased in frequency of late as threat actors begin to grasp just how efficient they can be, and his post documents an alarming number of these incidents since 2024.

“While security firms appear to be doing a good job spotting this, we’re also gonna need GitHub’s security team to step up,” Cimpanu wrote. “Unfortunately, on a platform designed to copy (fork) a project and create new versions of it (clones), spotting malicious additions to clones of legitimate repos might be quite the engineering problem to fix.”

Update, 2:40 p.m. ET: Wiz is reporting that TeamPCP also pushed credential stealing malware to the KICS vulnerability scanner from Checkmarx, and that the scanner’s GitHub Action was compromised between 12:58 and 16:50 UTC today (March 23rd).