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Anthropic Users Hit by Infostealer Attacks, Session Thefts

A threat actor used multiple infostealers to harvest session data and hijack Claude accounts belonging to an unknown number of users.

Dark Reading reports that a threat actor deployed a variety of infostealer families to collect session information, which was then used to access Claude accounts belonging to an unknown number of users. Anthropic has not disclosed the scale of the compromise. The incident underscores session token theft via infostealer logs as an effective route into AI platform accounts.

Dark Reading · 16d agoMalware in the wild

Anthropic cracks down on hijacked user accounts mining AI tokens

Commodity infostealer malware hijacked Anthropic user accounts, letting criminals mine AI tokens on victims' paid usage; Anthropic cracked down on affected accounts.

The Register reports that Anthropic is cracking down on user accounts hijacked through commodity malware that steals authenticated browser sessions. With the stolen sessions, thieves ran AI workloads to mine tokens, freeloading on victims' paid usage allowances. The campaign illustrates how infostealer operators now monetize AI platform credentials and sessions, not just financial accounts.

The Register · Security · 16d agoMalware in the wild1

Infostealers Are Hijacking Claude Sessions and Draining Subscriptions

Infostealers hijacked active Claude sessions to bypass 2FA, drain paid usage and run unauthorized charges; Anthropic is revoking sessions and refunding.

Anthropic confirmed that infostealer malware on user machines stole active Claude login sessions, letting attackers bypass passwords, MFA, and SSO and drain paid usage and run unauthorized charges. Affected families identified on Windows include Vidar, LummaC2, StealC, RedLine, and Acreed, plus Atomic Stealer on a small number of Macs; the malware typically arrived via unofficial downloads or malicious apps. Anthropic signed users out, removed saved payment cards, revoked affected sessions, and is refunding unauthorized charges, noting phones and tablets were not involved.

Security Affairs · 16d agoMalware in the wild

Threat Actors Are Posing as OpenAI, Anthropic and DeepSeek to Target Credentials and Secrets

GreyNoise observes scanners spoofing OpenAI, Anthropic, and DeepSeek crawler user agents to hunt leaked credentials and secrets.

GreyNoise is observing automated scanners that pose as the web crawlers of OpenAI, Anthropic, DeepSeek, and Fortune 500 companies. The scanners use forged user agents while requesting files where misconfigured web servers frequently leak secrets and credentials. This activity abuses trust in AI crawler traffic to discover exposed credentials for follow-on attacks.

GreyNoise · 20d agoExploit / PoC in the wild

The sexy AI-powered dating app scams are here

Anthropic exposed a network of roughly 28 AI-driven dating apps using autonomous personas and gig workers to defraud paying users.

Anthropic threat intelligence uncovered a fraud network of around 28 dating apps after a prepaid account sent over 100,000 Claude API requests daily, with most chats run by autonomous AI personas and no human agent. Researchers Matthew Gore-Kormanik and Anthropic's Chris Cronbaugh documented apps including Dora, Romi, and Doni, which monetize conversations via coins; gig workers were hired only to pass liveness checks and select pregenerated replies. An operations manual written in Chinese was found inside the Doni app, and Anthropic published findings in its September 2026 AI misuse report.

The Verge · AI · 18h agoPhishing & fraud in the wild

Infostealers are hijacking Claude accounts at users’ expense

Malwarebytes reports infostealers are stealing Claude session cookies to hijack Anthropic accounts and consume victims' usage at their expense.

Anthropic warned that infostealer malware operators are harvesting Claude session cookies from infected machines. Attackers replay the stolen cookies to take over users' accounts and consume their usage quotas, affecting the victims' own access. The activity involves observed account hijacking rather than a flaw in Claude itself.

Malwarebytes Labs · 15d agoMalware in the wild

Infostealer Logs Expose Replayable AI Tokens That Can Bypass MFA

Okta finds infostealer logs contain thousands of replayable AI session tokens and API keys, letting criminals bypass MFA and access services from Google, Anthropic and OpenAI.

Okta analyzed a 7 GB infostealer dump from August 2, 2026 covering 5,871 infected machines in 162 countries and found 555 of 44,791 JWTs related to AI services, plus 1,843 unexpired JWTs and JWEs (largely set by OpenAI via NextAuth.js) and 24 still-valid API keys for Google Gemini, OpenAI, Groq and OpenRouter. Valid session tokens and API keys can be replayed with anti-detect browsers like Camoufox to bypass credential and MFA checks, fueling an underground market for AI account access known as LLMjacking, where attackers rack up victims' AI compute bills. Some 17.7% of the JWTs contained plaintext PII usable for social engineering. Google's GTIG reported growing buyer demand for Claude, Gemini, Cursor and Devin credentials, and Mandiant handled an incident where an actor used an exposed GitHub PAT to deploy unauthorized AI infrastructure and scale high-performance compute.

The Hacker News · 7d agoThreat actor in the wild1

Threat actors are posing as AI crawlers to hunt for exposed credentials

GreyNoise observed scanners spoofing AI crawler user agents from 824 IPs to harvest .env files and cloud credentials; no confirmed theft.

GreyNoise researchers found attackers disguising automated scanning as AI crawler traffic, using six crawler names from four AI companies including Anthropic's ClaudeBot, OpenAI, Google, and Perplexity. Between July 28 and August 23, 2026, the six names arrived from 824 IP addresses spread across 795 /24 networks that matched no published vendor ranges, shared one HTTP client fingerprint that had used more than 1,500 user agent strings, and never requested /robots.txt. The scanners targeted /.env, /.env.production, /.env.bak, and /.aws/credentials, hunting secrets, cloud access keys, private keys, and password stores, while forged Amazon crawler names appeared at greater volume under undocumented user agents. GreyNoise could not confirm whether any file was returned or any organization affected, and published all 824 addresses and targeted paths for defenders.

Help Net Security · 17d agoThreat actor

ThreatsDay: Gogs 10.0 RCE, n8n Workflow-to-RCE, $10M Reward, GLM

Hacker News ThreatsDay roundup: Defender BTR.sys driver abuse, DoJ charges 17 Mabna Institute members over IRGC-linked intrusions, Grandoreiro sideloading, OpenAI monitoring.

Check Point researchers showed Microsoft's signed Defender Boot-Time Removal driver (BTR.sys) can be repurposed as a universal kernel operation engine to bypass endpoint security without BYOVD. The DoJ charged 17 members of Iran's Mabna Institute, which on behalf of the IRGC stole over 31 TB of academic data from 144 US universities and compromised roughly 8,000 of 100,000 targeted professor accounts; the State Department offered a $10 million reward for five defendants. Separately, Acronis tracked a Grandoreiro campaign abusing DLL sideloading in the Duplicate Files Finder app across Latin America and Spain, while ErrTraffic ClickFix campaigns deliver Cruciferra (BYOVD) and Remus Stealer. OpenAI also previewed Private Safety Processing, a privacy-centric approach to monitoring model misuse without retaining customer content.

The Hacker News · 27d agoThreat actor1