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.
Infostealers Target Claude, Cursor, Codex and Other AI Agents to Steal Credentials and Sensitive Data
Gen Digital researchers report infostealer families Amatera, Remus and CallbackBeaver now harvest Claude, Cursor and Codex agent data, including tokens and MCP configs.
Gen Digital researchers found commodity infostealers extending their collection rules to local AI coding agent data from Claude, Cursor, Codex, Cline, Continue and OpenCode on Windows and macOS. Amatera targets Cline and Continue, Remus targets Claude, Cursor and OpenCode, and CallbackBeaver added Claude and Cursor with more than 5,000 samples observed in 30 days; Djinn Stealer hits Claude, Codex, Gemini, Cline, OpenCode and Kilo on macOS. Stolen data includes access and refresh tokens, prompt histories, conversation databases and MCP configurations holding API keys, potentially exposing connected source-control, cloud and ticketing systems. Remus is assessed as a Lumma Stealer variant using EtherHiding C2 resolution via Ethereum smart contracts.
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.
Fake Gemini installer delivers Vidar infostealer via Google Colab lure
Attackers used a fake Google Gemini installer hosted on Google Colab to deliver a Go-compiled Vidar infostealer that stole browser credentials from an EMEA company.
Darktrace investigated an EMEA company infection where the top search result for a Gemini-related filename pointed to a Google Colab page that redirected to a fake 'Windows Software Hub' hosting a malicious executable. The ZIP contained a README instructing victims to run the file as administrator and add it to antivirus exceptions, delivering a newer Go-compiled Vidar variant that used dtm[.]kijangturbo88[.]top over Telegram-based infrastructure. The malware stole browser credentials and other sensitive data; Darktrace's Autonomous Response blocked the C2 and quarantined the device.
Grand Theft Auto VI hype leads to malware
Fake GTA6 ISO downloads spread via SEO poisoning, torrents, and forums deliver NJRAT, DCRAT, an infostealer, and wiper ransomware.
Huntress analyzed a malicious ISO masquerading as a leaked Grand Theft Auto VI build; there is no official GTA6 demo or leaked playable copy. The fake gta6installer.exe shows a Russian 'license' message asking victims to email the attacker if the crack fails, then drops GTA6-branded files into %TEMP%. It installs multiple repurposed NJRAT copies (2023-era files) connecting to AWS-hosted IPs 35.157.111.131, 3.68.56.232, 3.67.15.169 and an ngrok tunnel, plus DCRAT communicating with a0700877.xsph.ru (141.8.197.42). The bundle also includes an infostealer and ransomware used as a wiper, in what appears to be an opportunistic, everything-at-once campaign.
REVSTEALER ramps up: analysis of up-and-coming infostealer
Elastic Security Labs analyzes REVSTEALER, an emerging infostealer harvesting browser credentials, cryptocurrency wallets, and gaming accounts.
Elastic Security Labs published a deep-dive analysis of REVSTEALER, described as an up-and-coming infostealer. The malware targets browser data, cryptocurrency wallets, and gaming accounts, with credential harvesting as its core function. The report tracks the family's capabilities as it ramps up activity 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.
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.
Infostealers Harvest 1.7 Billion Credentials in Six Months
Flashpoint reports infostealers harvested 1.7 billion credentials in the first half of 2026.
Threat intelligence firm Flashpoint found that infostealer malware was responsible for the theft of 1.7 billion credentials during the first half of 2026. The figure underscores the scale of commodity credential harvesting feeding downstream account takeover, fraud and ransomware operations.
MacSync Stealer: How a Google Search for Claude Led to a macOS Infostealer
Huntress dissects MacSync Stealer, a macOS infostealer delivered through fake Claude Code download pages in Google search results.
Huntress SOC analysts published a reverse-engineering analysis of MacSync Stealer, a macOS infostealer distributed through fraudulent Claude Code download pages surfaced via web searches. Users searching for Anthropic's Claude coding tool are redirected to fake download pages that install the stealer, abusing developer trust in popular AI tooling. The writeup covers the analysis of the sample and its delivery chain.