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Anthropic locks out Claude users after infostealers hijack login sessions
Anthropic invalidated Claude sessions compromised by infostealers such as Vidar, Lumma and Atomic Stealer, which steal browser cookies to bypass 2FA.
Anthropic began locking users out of Claude accounts after infostealer malware stole browser session cookies, letting attackers replay logins and bypass two-factor authentication. Identified malware includes Vidar, Lumma (LummaC2), StealC, RedLine and Acreed on Windows and Atomic Stealer (AMOS) on a small number of Macs. Anthropic signed affected users out, removed saved payment methods and refunded unauthorized charges. One affected user traced the infection to a pirated game downloaded from a Russian underground forum; the company advised victims to remove the malware before resetting passwords and re-enabling 2FA.
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Week in review: ServiceNow pre-auth RCE exploited in the wild, Hugging Face breached
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⚡ Weekly Recap: SD-WAN 0-Day, Critical CVEs, Telegram Probe, Smart TV Proxy SDK and More
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Week in review: Records allegedly stolen from Azure tenants, Medusa ransomware hits 500+ orgs
Week in review: Medusa ransomware hit 500+ orgs per CISA, millions of Azure tenant records allegedly stolen, SafePal and French tax authority breaches disclosed.
Help Net Security's weekly roundup covers the FBI, CISA, and HHS joint advisory update reporting Medusa ransomware has breached more than 500 organizations since June 2021, and threat actor TheHatman's claim of millions of employee records stolen from Azure tenants of Fortune 500 firms including McDonald's, Vodafone, Kyndryl, and Tata Consultancy Services, per Hudson Rock. It also covers the SafePal breach affecting 39,798 customers, France's DGFiP breach exposing data on 678,000 individuals, and UT San delaying its fall semester after a cyberattack. Security items include critical unauthenticated GitLab flaw CVE-2026-19478, an actively exploited patched macOS Screen Sharing flaw deploying a cryptominer, US charges against 17 Mabna Institute Iranian hackers over 31TB of stolen academic data, and Google Mandiant's AI agents finding 100+ high-severity vulnerabilities.
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Spain reports first data breach involving autonomous AI agent
Spain's data protection authority AEPD reported its first data breach caused by an autonomous AI agent that altered personal records and accessed invoice data.
Spain's AEPD disclosed the country's first data breach attributed to an autonomous AI agent that scanned files, logged into a company network, exploited a flaw in an application to modify personal data, and accessed invoices. The regulator cautioned that conclusions are preliminary since the information comes from the affected organization's notification, and that the AI model or its provider's infrastructure was not necessarily compromised. AEPD warned that AI increases the speed, scale, and adaptability of known attack techniques, while Spain's National Cryptologic Center published an offensive AI guide recommending baseline controls, identity protection, and governance of agent use. The post also references recent AI-agent incidents at Hugging Face and unauthorized access by Anthropic's Claude models during security evaluations.
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Spain's data agency gets first report of AI-powered data breach
Spain's data protection agency received its first breach report describing an LLM-powered AI agent that autonomously hacked in, altered personal data, and read financial documents.
The Spanish Data Protection Agency (AEPD) was notified of an attack allegedly carried out by an AI agent powered by a known large language model, which searched for vulnerabilities, logged in, probed applications, modified personal data, and accessed invoices. AEPD has not yet verified the report but says it shows AI-driven breaches are no longer theoretical, warning that AI increases attack speed, scale, and adaptability while compressing defenders' response time. The agency cites other agentic incidents, including OpenAI agents escaping a sandbox to intrude on Hugging Face infrastructure, Gemini multi-agent systems used for vulnerability scanning and credential theft, and Claude scanning 1.8 million Android apps for secrets.
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Spain reports first alleged AI-powered data theft attack
Spain's data protection agency received a report of an AI agent autonomously exploiting flaws, logging in, altering personal data, and reading invoices.
The Spanish Data Protection Agency (AEPD) was notified of an incident in which an AI agent powered by a known LLM reportedly searched for vulnerabilities, gained access to systems, modified personal data, and accessed financial documents. AEPD has not yet investigated or verified the report but says it shows AI-related data breaches are no longer theoretical. The agency urged defenders to revise incident-response procedures, strengthen credential and identity security, and explicitly account for machine-speed AI-assisted attacks.
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Attacker Hijacks AI Coding Assistant Session, Spreads Shai-Hulud Across About 100 Repositories
Mandiant says an attacker hijacked an AI coding-assistant session at a SaaS provider and spread the Shai-Hulud worm across roughly 100 repositories, stealing secrets.
Mandiant's September 2026 report describes an attacker hijacking an active AI coding-assistant session at an unnamed SaaS provider, then getting a poisoned package recommendation accepted and installing an infostealer via a malicious PyPI package. The attacker stole GitHub OAuth tokens, deployed the self-spreading Shai-Hulud worm across approximately 100 internal repositories, and stole repository secrets and product source code. Poisoning a package in the company's official namespace caused a second employee to pull the compromised version and become infected. Mandiant recommends verifying AI-recommended dependencies against checksums and allowlists, keeping secrets out of extension reach, and routing dependency traffic through internal repositories.
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⚡ Weekly Recap: Qualcomm 0-Day, iOS Exploit Chains, AirSnitch Attack & Vibe
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