The U.S. Justice Department joined authorities in Canada and Germany in dismantling the online infrastructure behind four highly disruptive botnets that compromised more than three million hacked Internet of Things (IoT) devices, such as routers and web cameras. The feds say the four botnets -- named Aisuru, Kimwolf, JackSkid and Mossad -- are responsible for a series of recent record-smashing distributed denial-of-service (DDoS) attacks capable of knocking nearly any target offline.

A hacktivist group with links to Iran's intelligence agencies is claiming responsibility for a data-wiping attack against Stryker, a global medical technology company based in Michigan. News reports out of Ireland, Stryker's largest hub outside of the United States, said the company sent home more than 5,000 workers there today. Meanwhile, a voicemail message at Stryker's main U.S. headquarters says the company is currently experiencing a building emergency.

Microsoft Corp. today pushed security updates to fix at least 77 vulnerabilities in its Windows operating systems and other software. There are no pressing "zero-day" flaws this month (compared to February's five zero-day treat), but as usual some patches may deserve more rapid attention from organizations using Windows. Here are a few highlights from this month's Patch Tuesday.

AI-based assistants or "agents" -- autonomous programs that have access to the user's computer, files, online services and can automate virtually any task -- are growing in popularity with developers and IT workers. But as so many eyebrow-raising headlines over the past few weeks have shown, these powerful and assertive new tools are rapidly shifting the security priorities for organizations, while blurring the lines between data and code, trusted co-worker and insider threat, ninja hacker and novice code jockey.

In early January 2026, KrebsOnSecurity revealed how a security researcher disclosed a vulnerability that was used to assemble Kimwolf, the world's largest and most disruptive botnet. Since then, the person in control of Kimwolf -- who goes by the handle "Dort" -- has coordinated a barrage of distributed denial-of-service (DDoS), doxing and email flooding attacks against the researcher and this author, and more recently caused a SWAT team to be sent to the researcher's home. This post examines what is knowable about Dort based on public information.

Most phishing websites are little more than static copies of login pages for popular online destinations, and they are often quickly taken down by anti-abuse activists and security firms. But a stealthy new phishing-as-a-service offering lets customers sidestep both of these pitfalls: It uses cleverly disguised links to load the target brand's real website, and then acts as a relay between the target and the legitimate site -- forwarding the victim's username, password and multi-factor authentication (MFA) code to the legitimate site and returning its responses.

For the past week, the massive "Internet of Things" (IoT) botnet known as Kimwolf has been disrupting the The Invisible Internet Project (I2P), a decentralized, encrypted communications network designed to anonymize and secure online communications. I2P users started reporting disruptions in the network around the same time the Kimwolf botmasters began relying on it to evade takedown attempts against the botnet's control servers.

Microsoft today issued patches to plug at least 113 security holes in its various Windows operating systems and supported software. Eight of the vulnerabilities earned Microsoft's most-dire "critical" rating, and the company warns that attackers are already exploiting one of the bugs fixed today.

Our first story of 2026 revealed how a destructive new botnet called Kimwolf rapidly grew to infect more than two million devices by mass-compromising a vast number of unofficial Android TV streaming boxes. Today, we'll dig through digital clues left behind by the hackers, network operators, and cybercrime services that appear to have benefitted from Kimwolf's spread.

The story you are reading is a series of scoops nestled inside a far more urgent Internet-wide security advisory. The vulnerability at issue has been exploited for months already, and it's time for a broader awareness of the threat. The short version is that everything you thought you knew about the security of the internal network behind your Internet router probably is now dangerously out of date.

KrebsOnSecurity.com celebrates its 16th anniversary today! A huge "thank you" to all of our readers -- newcomers, long-timers and drive-by critics alike. Your engagement this past year here has been tremendous and truly a salve on a handful of dark days. Happily, comeuppance was a strong theme running through our coverage in 2025, with a primary focus on entities that enabled complex and globally-dispersed cybercrime services.

The Trump administration has pursued a staggering range of policy pivots this past year that threaten to weaken the nation’s ability and willingness to address a broad spectrum of technology challenges, from cybersecurity and privacy to countering disinformation, fraud and corruption. These shifts, along with the president’s efforts to restrict free speech and freedom of the press, have come at such a rapid clip that many readers probably aren’t even aware of them all.

Direct navigation -- the act of visiting a website by manually typing a domain name in a web browser -- has never been riskier: A new study finds the vast majority of "parked" domains -- mostly expired or dormant domain names, or common misspellings of popular websites -- are now configured to redirect visitors to sites that foist scams and malware.

Microsoft today pushed updates to fix at least 56 security flaws in its Windows operating systems and supported software. This final Patch Tuesday of 2025 tackles one zero-day bug that is already being exploited, as well as two publicly disclosed vulnerabilities.

A sprawling academic cheating network turbocharged by Google Ads that has generated nearly $25 million in revenue has curious connections to a Kremlin-connected oligarch whose Russian university builds drones for Russia's war against Ukraine.

China-based phishing groups blamed for non-stop scam SMS messages about a supposed wayward package or unpaid toll fee are promoting a new offering, just in time for the holiday shopping season: Phishing kits for mass-creating fake but convincing e-commerce websites that convert customer payment card data into mobile wallets from Apple and Google. Experts say these same phishing groups also are now using SMS lures that promise unclaimed tax refunds and mobile rewards points.

A prolific cybercriminal group that calls itself "Scattered LAPSUS$ Hunters" made headlines regularly this year by stealing data from and publicly mass extorting dozens of major corporations. But the tables seem to have turned somewhat for "Rey," the moniker chosen by the technical operator and public face of the hacker group: Earlier this week, Rey confirmed his real life identity and agreed to an interview after KrebsOnSecurity tracked him down and contacted his father.

On the surface, the Superbox media streaming devices for sale at retailers like BestBuy and Walmart may seem like a steal: They offer unlimited access to more than 2,200 pay-per-view and streaming services like Netflix, ESPN and Hulu, all for a one-time fee of around $400. But security experts warn these TV boxes require intrusive software that forces the user's network to relay Internet traffic for others, traffic that is often tied to cybercrime activity such as advertising fraud and account takeovers.

In March 2024, Mozilla said it was winding down its collaboration with Onerep -- an identity protection service offered with the Firefox web browser that promises to remove users from hundreds of people-search sites -- after KrebsOnSecurity revealed Onerep's founder had created dozens of people-search services and was continuing to operate at least one of them. Sixteen months later, however, Mozilla is still promoting Onerep. This week, Mozilla announced their partnership with Onerep will officially end next month.

An intermittent outage at Cloudflare on Tuesday briefly knocked many of the Internet's top destinations offline. Some affected Cloudflare customers were able to pivot away from the platform temporarily so that visitors could still access their websites. But security experts say doing so may have also triggered an impromptu network penetration test for organizations that have come to rely on Cloudflare to block many types of abusive and malicious traffic.

Microsoft this week pushed security updates to fix more than 60 vulnerabilities in its Windows operating systems and supported software, including at least one zero-day bug that is already being exploited. Microsoft also fixed a glitch that prevented some Windows 10 users from taking advantage of an extra year of security updates, which is nice because the zero-day flaw and other critical weaknesses patched today affect all versions of Windows, including Windows 10.

Google is suing more than two dozen unnamed individuals allegedly involved in peddling a popular China-based mobile phishing service that helps scammers impersonate hundreds of trusted brands, blast out text message lures, and convert phished payment card data into mobile wallets from Apple and Google.

The U.S. government is reportedly preparing to ban the sale of wireless routers and other networking gear from TP-Link Systems, a tech company that currently enjoys an estimated 50% market share among home users and small businesses. Experts say while the proposed ban may have more to do with TP-Link's ties to China than any specific technical threats, much of the rest of the industry serving this market also sources hardware from China and ships products that are insecure fresh out of the box.

For the past week, domains associated with the massive Aisuru botnet have repeatedly usurped Amazon, Apple, Google and Microsoft in Cloudflare's public ranking of the most frequently requested websites. Cloudflare responded by redacting Aisuru domain names from their top websites list. The chief executive at Cloudflare says Aisuru's overlords are using the botnet to boost their malicious domain rankings, while simultaneously attacking the company's domain name system (DNS) service.

A Ukrainian man indicted in 2012 for conspiring with a prolific hacking group to steal tens of millions of dollars from U.S. businesses was arrested in Italy and is now in custody in the United States, KrebsOnSecurity has learned.

Sources close to the investigation say Yuriy Igorevich Rybtsov, a 41-year-old from the Russia-controlled city of Donetsk, Ukraine, was previously referenced in U.S. federal charging documents only by his online handle "MrICQ." According to a 13-year-old indictment filed by prosecutors in Nebraska, MrICQ was a developer for a cybercrime group known as "Jabber Zeus."

Aisuru, the botnet responsible for a series of record-smashing distributed denial-of-service (DDoS) attacks this year, recently was overhauled to support a more low-key, lucrative and sustainable business: Renting hundreds of thousands of infected Internet of Things (IoT) devices to proxy services that help cybercriminals anonymize their traffic. Experts says a glut of proxies from Aisuru and other sources is fueling large-scale data harvesting efforts tied to various artificial intelligence (AI) projects, helping content scrapers evade detection by routing their traffic through residential connections that appear to be regular Internet users.

Financial regulators in Canada this week levied $176 million in fines against Cryptomus, a digital payments platform that supports dozens of Russian cryptocurrency exchanges and websites hawking cybercrime services. The penalties for violating Canada's anti money-laundering laws come ten months after KrebsOnSecurity noted that Cryptomus's Vancouver street address was home to dozens of foreign currency dealers, money transfer businesses, and cryptocurrency exchanges — none of which were physically located there.

Cybercriminals are abusing a widespread lack of authentication in the customer service platform Zendesk to flood targeted email inboxes with menacing messages that come from hundreds of Zendesk corporate customers simultaneously.

Microsoft today released software updates to plug a whopping 172 security holes in its Windows operating systems, including at least three vulnerabilities that are already being actively exploited. October's Patch Tuesday also marks the final month that Microsoft will ship security updates for Windows 10 systems. If you're running a Windows 10 PC and you're unable or unwilling to migrate to Windows 11, read on for other options.

The world's largest and most disruptive botnet is now drawing a majority of its firepower from compromised Internet-of-Things (IoT) devices hosted on U.S. Internet providers like AT&T, Comcast and Verizon, new evidence suggests. Experts say the heavy concentration of infected devices at U.S. providers is complicating efforts to limit collateral damage from the botnet's attacks, which shattered previous records this week with a brief traffic flood that clocked in at nearly 30 trillion bits of data per second.