ShieldBreak: New Windows Zero-Day Bypasses Microsoft’s RoguePlanet Patch
Researcher Chaotic Eclipse published a PoC bypassing Microsoft's CVE-2026-50656 Defender patch, enabling SYSTEM-level code execution on fully patched Windows systems.
Security researcher Chaotic Eclipse released a proof-of-concept for ShieldBreak, a Microsoft Defender zero-day that fully bypasses the patch for CVE-2026-50656 (RoguePlanet), a race condition in the Malware Protection Engine (mpengine.dll) allowing SYSTEM-level code execution. The PoC was tested on Windows 11 25H2 and Windows Server 2025 with a 100% success rate, and Windows 10 is also vulnerable though not supported by the PoC; the flaw may also leak 8 bytes of memory. Microsoft's MSRC had criticized the researcher's repeated uncoordinated disclosures, including YellowKey (BitLocker bypass), GreenPlasma, and LegacyHive (User Profile Service LPE).
Russian State-Sponsored Hackers Use Claude to Rebuild Malware After Detection
Anthropic disrupted APT29-linked GTG-20006, which used Claude to autonomously rebuild malware, hijack hotel Wi-Fi DNS, and target 20-plus Ukrainian, European, and US-linked organizations.
Anthropic attributed the campaign to GTG-20006, aligned with Midnight Blizzard (APT29/Cozy Bear), which developed an AI-driven process that monitors its implants against security products and autonomously rebuilds and redeploys detected malware. Targets included military intelligence, diplomatic, and defense organizations in Ukraine and Europe, plus Middle East and Asian maritime agencies; the actor compromised at least three hotel Wi-Fi vendors via DNS hijacking and served ClickFix lures delivering Windows, Android, and iOS malware such as PowerChrome, GiftDrop, and DarkSword. Operations also included a North African breach exfiltrating over 300,000 national identity records and 500,000-plus company registry entries, an Embassy Kit device-code phishing campaign stealing Microsoft 365 tokens from at least eight organizations, and WhatsApp account takeover using headless browsers. The campaign overlaps with CaptiveCrunch reporting from ReliaQuest, Microsoft, Google, and Lumen Black Lotus Labs.
Countering misuse of AI: September 2026 / Anthropic
Anthropic publishes threat intelligence on Claude misuse across seven harm areas from December 2025 through August 2026.
Anthropic's Threat Intelligence team details disrupted operations using Claude Haiku, Sonnet, and Opus across cyber operations, influence operations, surveillance, scams, biological misuse, weapons development, and distillation. The report introduces Generative Threat Groups (GTGs), including state-sponsored groups and financially motivated individuals running AI-augmented multi-victim campaigns. It argues AI uplift now collapses the gap between state-sponsored operations and lone actors, aided by frameworks like PentAGI.
Hackers Abuse Claude AI Agents to Automate Cyberattacks, Exploitation and Data Theft
Anthropic reports actors including GTG-20006 (Midnight Blizzard-linked) and ShinyHunters clusters abused Claude AI agents to automate phishing, credential harvesting, and data theft against 20+ organizations.
Anthropic's September 2026 threat intelligence report describes threat actors operating multi-agent workflows built on Claude models to automate the cyber kill chain, from reconnaissance and phishing to exfiltration. The group GTG-20006, assessed as consistent with Midnight Blizzard, targeted Ukrainian and European government, diplomatic, defense, and intelligence entities plus the drone supply chain, with more than 20 organizations identified. Clusters tied to ShinyHunters used 10 AWS EC2 instances to decompile 1.8 million Android APKs for hard-coded secrets and, in a separate SaaS supply chain intrusion, dumped over 2,100 Azure AD token sets across 40+ corporate tenants in about 34 hours. Reported malware families include PowerChrome, WUEngine, Shadow C2, MiniPlasma, CloudSyncSvc, the GiftDrop Android RAT, and the DarkSword iOS exploit chain.