Krebs on Security

Netherlands Seizes 800 Servers, Arrests 2 for Aiding Cyberattacks

May 25, 2026

Authorities in the Netherlands have arrested the co-owners of two related Internet hosting companies for operating IT infrastructure used by Russia to carry out cyberattacks, influence operations and disinformation campaigns inside the European Union. The two men were the focus of a 2025 KrebsOnSecurity story about how their hosting companies had assumed control over the technical infrastructure of Stark Industries Solutions, an Internet service provider sanctioned last year by the EU as a frequent staging ground for cyber mischief from Russia’s intelligence agencies.

An investigator with the Tax Intelligence and Investigation Service (FIOD), the Dutch financial crimes agency, during the raid. Image: FIOD.

The Dutch daily news outlet de Volkskrant reports that the Dutch financial crime agency FIOD on May 18 arrested a 57-year-old from Amsterdam and a 39-year-old from The Hague, charging them with violating sanctions law by directly or indirectly making economic resources available to EU-sanctioned entities.

The Dutch investigation focuses on Stark Industries, a sprawling hosting provider that materialized just two weeks before Russia invaded Ukraine. As detailed in this May 2024 deep-dive, Stark quickly became the source of massive distributed denial-of-service (DDoS) attacks against European targets, and emerged as a top supplier of proxy and anonymity services that showed up time and again in cyberattacks linked to Russia-backed hacking groups.

That report identified two Moldovan brothers — Ivan and Yuri Neculiti and their company PQHosting — who were providing one of Stark’s two main conduits to the larger Internet. In May 2025, the EU sanctioned PQHosting and the Neculiti brothers for aiding Russia’s hybrid warfare efforts. But as KrebsOnSecurity observed in September 2025, those sanctions failed to target Stark’s remaining connection to the Internet — an Internet service provider based in the Netherlands called MIRhosting.

MIRhosting is operated by Andrey Nesterenko, a 39-year-old Russian native who runs the business out of the Netherlands. News that PQHosting and the Neculiti brothers were about to be sanctioned by the EU leaked in the media nearly two weeks before the sanctions were announced last year. During that time, the Stark network assets were transferred from PQHosting to a new entity called the[.]hosting, under the control of the Dutch entity WorkTitans BV.

And as our September 2025 report showed, WorkTitans was controlled by Nesterenko and a 57-year-old from Amsterdam named Youssef Zinad. On top of that, WorkTitans was getting connectivity to the larger Internet solely through MIRhosting, where Zinad had worked previously.

On May 18, Dutch financial crime investigators arrested Nesterenko and Zinad, and searched three businesses in Enschede and Almere and two data centers in Dronten and Schiphol-Rijk. A statement from the Dutch authorities said they also seized laptops, telephones and more than 800 servers.

A message to the-hosting customers immediately after 800 of its servers were seized by Dutch authorities. The message says that unfortunately data stored on the server has been lost and cannot be recovered.

De Volkskrant said it reviewed data showing WorkTitans and MIRhosting were the most-used networks in pro-Russian attacks on Danish government bodies between November 13 and 19, 2025, the week of Denmark’s municipal elections. Continue reading →

Lawmakers Demand Answers as CISA Tries to Contain Data Leak

May 22, 2026

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Lawmakers in both houses of Congress are demanding answers from the U.S. Cybersecurity & Infrastructure Security Agency (CISA) after KrebsOnSecurity reported this week that a CISA contractor intentionally published AWS GovCloud keys and a vast trove of other agency secrets on a public GitHub account. The inquiry comes as CISA is still struggling to contain the breach and invalidate the leaked credentials.

On May 18, KrebsOnSecurity reported that a CISA contractor with administrative access to the agency’s code development platform had created a public GitHub profile called “Private-CISA” that included plaintext credentials to dozens of internal CISA systems. Experts who reviewed the exposed secrets said the commit logs for the code repository showed the CISA contractor disabled GitHub’s built-in protection against publishing sensitive credentials in public repos.

CISA acknowledged the leak but has not responded to questions about the duration of the data exposure. However, experts who reviewed the now-defunct Private-CISA archive said it was originally created in November 2025, and that it exhibits a pattern consistent with an individual operator using the repository as a working scratchpad or synchronization mechanism rather than a curated project repository.

In a written statement, CISA said “there is no indication that any sensitive data was compromised as a result of the incident.” But in a May 19 a letter (PDF) to CISA’s Acting Director Nick Andersen, Sen. Maggie Hassan (D-NH) said the credential leak raises serious questions about how such a security lapse could occur at the very agency charged with helping to prevent cyber breaches.

“This reporting raises serious concerns regarding CISA’s internal policies and procedures at a time of significant cybersecurity threats against U.S. critical infrastructure,” Sen. Hassan wrote.

A May 19 letter from Sen. Margaret Hassan (D-NH) to the acting director of CISA demanded answers to a dozen questions about the breach.

Sen. Hassan noted that the incident occurred against the backdrop of major disruptions internally at CISA, which lost more than a third of it workforce and almost all of its senior leaders after the Trump administration forced a series of early retirements, buyouts, and resignations across the agency’s various divisions.

Rep. Bennie Thompson (D-MS), the ranking member on the House Homeland Security Committee, echoed the senator’s concerns.

“We are concerned that this incident reflects a diminished security culture and/or an inability for CISA to adequately manage its contract support,” Thompson wrote in a May 19 letter to the acting CISA chief that was co-signed by Rep. Delia Ramirez (D-Ill), the ranking member of the panel’s Subcommittee on Cybersecurity and Infrastructure Protection. “It’s no secret that our adversaries — like China, Russia, and Iran — seek to gain access to and persistence on federal networks. The files contained in the ‘Private-CISA’ repository provided the information, access, and roadmap to do just that.”

KrebsOnSecurity has learned that more a week after CISA was first notified of the data leak by the security firm GitGuardian, the agency is still working to invalidate and replace many of the exposed keys and secrets.

On May 20, KrebsOnSecurity heard from Dylan Ayrey, the creator of TruffleHog, an open-source tool for discovering private keys and other secrets buried in code hosted at GitHub and other public platforms. Ayrey said CISA still hadn’t invalidated an RSA private key exposed in the Private-CISA repo that granted access to a GitHub app which is owned by the CISA enterprise account and installed on the CISA-IT GitHub organization with full access to all code repositories.

“An attacker with this key can read source code from every repository in the CISA-IT organization, including private repos, register rogue self-hosted runners to hijack CI/CD pipelines and access repository secrets, and modify repository admin settings including branch protection rules, webhooks, and deploy keys,” Ayrey told KrebsOnSecurity. CI/CD stands for Continuous Integration and Continuous Delivery, and it refers to a set of practices used to automate the building, testing and deployment of software. Continue reading →

Alleged Kimwolf Botmaster ‘Dort’ Arrested, Charged in U.S. and Canada

May 21, 2026

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Canadian authorities on Wednesday arrested a 23-year-old Ottawa man on suspicion of building and operating Kimwolf, a fast spreading Internet-of-Things botnet that enslaved millions of devices for use in a series of massive distributed denial-of-service (DDoS) attacks over the past six months. KrebsOnSecurity publicly named the suspect in February 2026 after the accused launched a volley of DDoS, doxing and swatting campaigns against this author and a security researcher. He now faces criminal hacking charges in both Canada and the United States.

A criminal complaint unsealed today in an Alaska district court charges Jacob Butler, a.k.a. “Dort,” of Ottawa, Canada with operating the Kimwolf DDoS botnet. A statement from the Department of Justice says the complaint against Butler was unsealed following the defendant’s arrest in Canada by the Ontario Provincial Police pursuant to a U.S. extradition warrant. Butler is currently in Canadian custody awaiting an initial court hearing scheduled for early next week.

The government said Kimwolf targeted infected devices which were traditionally “firewalled” from the rest of the internet, such as digital photo frames and web cameras. The infected systems were then rented to other cybercriminals, or forced to participate in record-smashing DDoS attacks, as well as assaults that affected Internet address ranges for the Department of Defense. Consequently, the DoD’s Defense Criminal Investigative Service is investigating the case, with assistance from the FBI field office in Anchorage.

“KimWolf was tied to DDoS attacks which were measured at nearly 30 Terabits per second, a record in recorded DDoS attack volume,” the Justice Department statement reads. “These attacks resulted in financial losses which, for some victims, exceeded one million dollars. The KimWolf botnet is alleged to have issued over 25,000 attack commands.”

On March 19, U.S. authorities joined international law enforcement partners in seizing the technical infrastructure for Kimwolf and three other large DDoS botnets — named Aisuru, JackSkid and Mossad — that were all competing for the same pool of vulnerable devices.

On February 28, KrebsOnSecurity identified Butler as the Kimwolf botmaster after digging through his various email addresses, registrations on the cybercrime forums, and posts to public Telegram and Discord servers. However, Dort continued to threaten and harass researchers who helped track down his real-life identity and dramatically slow the spread of his botnet.

Dort claimed responsibility for at least two swatting attacks targeting the founder of Synthient, a security startup that helped to secure a widespread critical security weakness that Kimwolf was using to spread faster and more effectively than any other IoT botnet out there. Synthient was among many technology companies thanked by the Justice Department today, and Synthient’s founder Ben Brundage told KrebsOnSecurity he’s relieved Butler is in custody.

“Hopefully this will end the harassment,” Brundage said.

An excerpt from the criminal complaint against Butler, detailing how he ordered a swatting attack against Ben Brundage, the founder of the security firm Synthient.

Continue reading →

CISA Admin Leaked AWS GovCloud Keys on Github

May 18, 2026

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Until this past weekend, a contractor for the Cybersecurity & Infrastructure Security Agency (CISA) maintained a public GitHub repository that exposed credentials to several highly privileged AWS GovCloud accounts and a large number of internal CISA systems. Security experts said the public archive included files detailing how CISA builds, tests and deploys software internally, and that it represents one of the most egregious government data leaks in recent history.

On May 15, KrebsOnSecurity heard from Guillaume Valadon, a researcher with the security firm GitGuardian. Valadon’s company constantly scans public code repositories at GitHub and elsewhere for exposed secrets, automatically alerting the offending accounts of any apparent sensitive data exposures. Valadon said he reached out because the owner in this case wasn’t responding and the information exposed was highly sensitive.

A redacted screenshot of the now-defunct “Private CISA” repository maintained by a CISA contractor.

The GitHub repository that Valadon flagged was named “Private-CISA,” and it harbored a vast number of internal CISA/DHS credentials and files, including cloud keys, tokens, plaintext passwords, logs and other sensitive CISA assets.

Valadon said the exposed CISA credentials represent a textbook example of poor security hygiene, noting that the commit logs in the offending GitHub account show that the CISA administrator disabled the default setting in GitHub that blocks users from publishing SSH keys or other secrets in public code repositories.

“Passwords stored in plain text in a csv, backups in git, explicit commands to disable GitHub secrets detection feature,” Valadon wrote in an email. “I honestly believed that it was all fake before analyzing the content deeper. This is indeed the worst leak that I’ve witnessed in my career. It is obviously an individual’s mistake, but I believe that it might reveal internal practices.”

One of the exposed files, titled “importantAWStokens,” included the administrative credentials to three Amazon AWS GovCloud servers. Another file exposed in their public GitHub repository — “AWS-Workspace-Firefox-Passwords.csv” — listed plaintext usernames and passwords for dozens of internal CISA systems. According to Caturegli, those systems included one called “LZ-DSO,” which appears short for “Landing Zone DevSecOps,” the agency’s secure code development environment.

Philippe Caturegli, founder of the security consultancy Seralys, said he tested the AWS keys only to see whether they were still valid and to determine which internal systems the exposed accounts could access. Caturegli said the GitHub account that exposed the CISA secrets exhibits a pattern consistent with an individual operator using the repository as a working scratchpad or synchronization mechanism rather than a curated project repository.

“The use of both a CISA-associated email address and a personal email address suggests the repository may have been used across differently configured environments,” Caturegli observed. “The available Git metadata alone does not prove which endpoint or device was used.”

The Private CISA GitHub repo exposed dozens of plaintext credentials for important CISA GovCloud resources.

Caturegli said he validated that the exposed credentials could authenticate to three AWS GovCloud accounts at a high privilege level. He said the archive also includes plain text credentials to CISA’s internal “artifactory” — essentially a repository of all the code packages they are using to build software — and that this would represent a juicy target for malicious attackers looking for ways to maintain a persistent foothold in CISA systems.

“That would be a prime place to move laterally,” he said. “Backdoor in some software packages, and every time they build something new they deploy your backdoor left and right.”

In response to questions, a spokesperson for CISA said the agency is aware of the reported exposure and is continuing to investigate the situation.

“Currently, there is no indication that any sensitive data was compromised as a result of this incident,” the CISA spokesperson wrote. “While we hold our team members to the highest standards of integrity and operational awareness, we are working to ensure additional safeguards are implemented to prevent future occurrences.” Continue reading →

Patch Tuesday, May 2026 Edition

May 12, 2026

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Artificial intelligence platforms may be just as susceptible to social engineering as human beings, but they are proving remarkably good at finding security vulnerabilities in human-made computer code. That reality is on full display this month with some of the more widely-used software makers — including Apple, Google, Microsoft, Mozilla and Oracle — fixing near record volumes of security bugs, and/or quickening the tempo of their patch releases.

As it does on the second Tuesday of every month, Microsoft today released software updates to address at least 118 security vulnerabilities in its various Windows operating systems and other products. Remarkably, this is the first Patch Tuesday in nearly two years that Microsoft is not shipping any fixes to deal with emergency zero-day flaws that are already being exploited. Nor have any of the flaws fixed today been previously disclosed (potentially giving attackers a heads up in how to exploit the weakness).

Sixteen of the vulnerabilities earned Microsoft’s most-dire “critical” label, meaning malware or miscreants could abuse these bugs to seize remote control over a vulnerable Windows device with little or no help from the user. Rapid7 has done much of the heavy lifting in identifying some of the more concerning critical weaknesses this month, including: Continue reading →

Canvas Breach Disrupts Schools & Colleges Nationwide

May 7, 2026

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An ongoing data extortion attack targeting the widely-used education technology platform Canvas disrupted classes and coursework at school districts and universities across the United States today, after a cybercrime group defaced the service’s login page with a ransom demand that threatened to leak data from 275 million students and faculty across nearly 9,000 educational institutions.

A screenshot shared by a reader showing the extortion message that was shown on the Canvas login page today.

Canvas parent firm Instructure responded to today’s defacement attacks by disabling the platform, which is used by thousands of schools, universities and businesses to manage coursework and assignments, and to communicate with students.

Instructure acknowledged a data breach earlier this week, after the cybercrime group ShinyHunters claimed responsibility and said they would leak data on tens of millions of students and faculty unless paid a ransom. The stated deadline for payment was initially set at May 6, but it was later pushed back to May 12.

In a statement on May 6, Instructure said the investigation so far shows the stolen information includes “certain identifying information of users at affected institutions, such as names, email addresses, and student ID numbers, as well as as messages among users.” The company said it found no evidence the breached data included more sensitive information, such as passwords, dates of birth, government identifiers or financial information.

The May 6 update stated that Canvas was fully operational, and that Instructure was not seeing any ongoing unauthorized activity on their platform. “At this stage, we believe the incident has been contained,” Instructure wrote.

However, by mid-day on Thursday, May 7, students and faculty at dozens of schools and universities were flooding social media sites with comments saying that a ransom demand from ShinyHunters had replaced the usual Canvas login page. Instructure responded by pulling Canvas offline and replacing the portal with the message, “Canvas is currently undergoing scheduled maintenance. Check back soon.”

“We anticipate being up soon, and will provide updates as soon as possible,” reads the current message on Instructure’s status page.

While the data stolen by ShinyHunters may or may not contain particularly sensitive information (ShinyHunters claims it includes several billion private messages among students and teachers, as well as names, phone numbers and email addresses), this attack could hardly have come at a worse time for Instructure: Many of the affected schools and universities are in the middle of final exams, and a prolonged outage could be highly damaging for the company.

The extortion message that greeted countless Canvas users today advised the affected schools to negotiate their own ransom payments to prevent the publication of their data — regardless of whether Instructure decides to pay.

“ShinyHunters has breached Instructure (again),” the extortion message read. “Instead of contacting us to resolve it they ignored us and did some ‘security patches.'”

A source close to the investigation who was not authorized to speak to the press told KrebsOnSecurity that a number of universities have already approached the cybercrime group about paying. The same source also pointed out that the ShinyHunters data leak blog no longer lists Instructure among its current extortion victims, and that the samples of data stolen from Canvas customers were removed as well. Data extortion groups like ShinyHunters will typically only remove victims from their leak sites after receiving an extortion payment or after a victim agrees to negotiate.

Dipan Mann, founder and CEO of the security firm Cloudskope, slammed Instructure for referring to today’s outage as a “scheduled maintenance” event on its status page. Mann said Shiny Hunters first demonstrated they’d breached Instructure on May 1, prompting Instructure’s Chief Information Security Officer Steve Proud to declare the following day that the incident had been contained. But Mann said today’s attack is at least the third time in the past eight months that Instructure has been breached by ShinyHunters.

In a blog post today, Mann noted that in September 2025, ShinyHunters released thousands of internal University of Pennsylvania files — donor records, internal memos, and other confidential materials — through what the Daily Pennsylvanian and other outlets later determined was, in part, a Canvas/Instructure-mediated access path.

“Penn was the named victim,” Mann wrote. “Instructure was the mechanism. The incident was treated as a Penn-specific story by most of the national press and quietly handled by Instructure as a customer-specific matter. That framing was wrong then. It is dramatically more wrong in light of the May 2026 events, which now look like the planned escalation of an attack pattern that ShinyHunters had been working against Instructure’s environment for at least eight months prior. The September 2025 Penn breach was the proof of concept. The May 1, 2026 incident was the production run. The May 7, 2026 recompromise was ShinyHunters demonstrating publicly that the May 2 ‘containment’ did not happen.” Continue reading →

Anti-DDoS Firm Heaped Attacks on Brazilian ISPs

April 30, 2026

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A Brazilian tech firm that specializes in protecting networks from distributed denial-of-service (DDoS) attacks has been enabling a botnet responsible for an extended campaign of massive DDoS attacks against other network operators in Brazil, KrebsOnSecurity has learned. The firm’s chief executive says the malicious activity resulted from a security breach and was likely the work of a competitor trying to tarnish his company’s public image.

An Archer AX21 router from TP-Link. Image: tp-link.com.

For the past several years, security experts have tracked a series of massive DDoS attacks originating from Brazil and solely targeting Brazilian ISPs. Until recently, it was less than clear who or what was behind these digital sieges. That changed earlier this month when a trusted source who asked to remain anonymous shared a curious file archive that was exposed in an open directory online.

The exposed archive contained several Portuguese-language malicious programs written in Python. It also included the private SSH authentication keys belonging to the CEO of Huge Networks, a Brazilian ISP that primarily offers DDoS protection to other Brazilian network operators.

Founded in Miami, Fla. in 2014, Huge Networks’s operations are centered in Brazil. The company originated from protecting game servers against DDoS attacks and evolved into an ISP-focused DDoS mitigation provider. It does not appear in any public abuse complaints and is not associated with any known DDoS-for-hire services.

Nevertheless, the exposed archive shows that a Brazil-based threat actor maintained root access to Huge Networks infrastructure and built a powerful DDoS botnet by routinely mass-scanning the Internet for insecure Internet routers and unmanaged domain name system (DNS) servers on the Web that could be enlisted in attacks.

DNS is what allows Internet users to reach websites by typing familiar domain names instead of the associated IP addresses. Ideally, DNS servers only provide answers to machines within a trusted domain. But so-called “DNS reflection” attacks rely on DNS servers that are (mis)configured to accept queries from anywhere on the Web. Attackers can send spoofed DNS queries to these servers so that the request appears to come from the target’s network. That way, when the DNS servers respond, they reply to the spoofed (targeted) address.

By taking advantage of an extension to the DNS protocol that enables large DNS messages, botmasters can dramatically boost the size and impact of a reflection attack — crafting DNS queries so that the responses are much bigger than the requests. For example, an attacker could compose a DNS request of less than 100 bytes, prompting a response that is 60-70 times as large. This amplification effect is especially pronounced when the perpetrators can query many DNS servers with these spoofed requests from tens of thousands of compromised devices simultaneously.

A DNS amplification attack, illustrated. It shows an attacker on the left, sending malicious commands to a number of bots to the immediate right, which then make spoofed DNS queries with the source address as the target's IP address.

A DNS amplification and reflection attack, illustrated. Image: veracara.digicert.com.

The exposed file archive includes a command-line history showing exactly how this attacker built and maintained a powerful botnet by scouring the Internet for TP-Link Archer AX21 routers. Specifically, the botnet seeks out TP-Link devices that remain vulnerable to CVE-2023-1389, an unauthenticated command injection vulnerability that was patched back in April 2023.

Malicious domains in the exposed Python attack scripts included DNS lookups for hikylover[.]st, and c.loyaltyservices[.]lol, both domains that have been flagged in the past year as control servers for an Internet of Things (IoT) botnet powered by a Mirai malware variant.

The leaked archive shows the botmaster coordinated their scanning from a Digital Ocean server that has been flagged for abusive activity hundreds of times in the past year. The Python scripts invoke multiple Internet addresses assigned to Huge Networks that were used to identify targets and execute DDoS campaigns. The attacks were strictly limited to Brazilian IP address ranges, and the scripts show that each selected IP address prefix was attacked for 10-60 seconds with four parallel processes per host before the botnet moved on to the next target.

The archive also shows these malicious Python scripts relied on private SSH keys belonging to Huge Networks’s CEO, Erick Nascimento. Reached for comment about the files, Mr. Nascimento said he did not write the attack programs and that he didn’t realize the extent of the DDoS campaigns until contacted by KrebsOnSecurity.

“We received and notified many Tier 1 upstreams regarding very very large DDoS attacks against small ISPs,” Nascimento said. “We didn’t dig deep enough at the time, and what you sent makes that clear.”

Nascimento said the unauthorized activity is likely related to a digital intrusion first detected in January 2026 that compromised two of the company’s development servers, as well as his personal SSH keys. But he said there’s no evidence those keys were used after January.

“We notified the team in writing the same day, wiped the boxes, and rotated keys,” Nascimento said, sharing a screenshot of a January 11 notification from Digital Ocean. “All documented internally.”

Mr. Nascimento said Huge Networks has since engaged a third-party network forensics firm to investigate further.

“Our working assessment so far is that this all started with a single internal compromise — one pivot point that gave the attacker downstream access to some resources, including a legacy personal droplet of mine,” he wrote. Continue reading →

‘Scattered Spider’ Member ‘Tylerb’ Pleads Guilty

April 21, 2026

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A 24-year-old British national and senior member of the cybercrime group “Scattered Spider” has pleaded guilty to wire fraud conspiracy and aggravated identity theft. Tyler Robert Buchanan admitted his role in a series of text-message phishing attacks in the summer of 2022 that allowed the group to hack into at least a dozen major technology companies and steal tens of millions of dollars worth of cryptocurrency from investors.

Buchanan’s hacker handle “Tylerb” once graced a leaderboard in the English-language criminal hacking scene that tracked the most accomplished cyber thieves. Now in U.S. custody and awaiting sentencing, the Dundee, Scotland native is facing the possibility of more than 20 years in prison.

A screenshot of two photos of Buchanan that appeared in a Daily Mail story dated May 3, 2025.

Two photos published in a Daily Mail story dated May 3, 2025 show Buchanan as a child (left) and as an adult being detained by airport authorities in Spain. “M&S” in this screenshot refers to Marks & Spencer, a major U.K. retail chain that suffered a ransomware attack last year at the hands of Scattered Spider.

Scattered Spider is the name given to a prolific English-speaking cybercrime group known for using social engineering tactics to break into companies and steal data for ransom, often impersonating employees or contractors to deceive IT help desks into granting access.

As part of his guilty plea, Buchanan admitted conspiring with other Scattered Spider members to launch tens of thousands of SMS-based phishing attacks in 2022 that led to intrusions at a number of technology companies, including Twilio, LastPass, DoorDash, and Mailchimp.

The group then used data stolen in those breaches to carry out SIM-swapping attacks that siphoned funds from individual cryptocurrency investors. In an unauthorized SIM-swap, crooks transfer the target’s phone number to a device they control and intercept any text messages or phone calls to the victim’s device — such as one-time passcodes for authentication and password reset links sent via SMS. The U.S. Justice Department said Buchanan admitted to stealing at least $8 million in virtual currency from individual victims throughout the United States. Continue reading →

Patch Tuesday, April 2026 Edition

April 14, 2026

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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. Continue reading →

Russia Hacked Routers to Steal Microsoft Office Tokens

April 7, 2026

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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. Continue reading →

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