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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

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

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

How Threat Actors Are Turning Trusted AI Platforms Into an Attack Surface

Huntress details campaigns abusing Claude Artifacts, claude.ai/share links, and ChatGPT/Grok conversations to deliver SectopRAT, MacSync, and AMOS stealers.

Huntress SOC documented nine months of campaigns in which attackers weaponized trusted AI platform features—Claude Artifacts, public claude.ai/share links, and indexable ChatGPT/Grok conversations—to deliver malware. The July FakeAgent campaign hit more than 29 organizations via a malicious Claude Artifact posing as a Claude Desktop download page that redirected to SectopRAT. A claude.ai/share link disguised as an Apple Support guide tricked a victim into running a curl command that deployed the MacSync stealer, harvesting cookies, credentials, keychain secrets, Telegram sessions, and SSH/cloud keys, while SEO-poisoned ChatGPT and Grok conversations delivered the AMOS stealer via ClickFix-style instructions.

BleepingComputer · 5d agoPhishing & fraud in the wild

Hackers Target Claude, Cursor and Codex AI Agents to Steal Tokens and Prompt Histories

Gen Digital found infostealers like Amatera and Remus stealing AI coding agent tokens, prompt histories, and MCP configs from infected Windows and macOS machines.

Gen Digital analysts observed Amatera and Remus detections among tens of thousands of protected Windows users over three months, with Amatera targeting Cline and Continue data and Remus targeting Claude, Cursor, and OpenCode. CallbackBeaver added Cursor and Claude to its collection scope with more than 5,000 samples in 30 days, while macOS-focused Djinn Stealer has been associated with Claude, Codex, Gemini, Cline, OpenCode, and Kilo. The stealers harvest access and refresh tokens, prompt histories, and MCP configuration files that can expose source control, ticketing, databases, cloud resources, and sensitive project context for follow-on fraud. Many stealers add targets via remotely managed rules, meaning this is an adaptation of existing infostealers rather than a new vulnerability in the AI tools themselves.

Cyber Security News · 7d agoMalware in the wild2

Attackers impersonate popular AI brands to spread malware

Sophos documented 38 MDR cases where attackers impersonated AI brands like Claude and Perplexity to deliver infostealers and backdoors.

Sophos X-Ops analyzed 12 months of MDR cases and confirmed 38 incidents involving AI. Software impersonation accounted for 30 cases, with Claude impersonated in 26; fake installers used an 'InstallFix' technique delivering mshta commands, in-memory payloads, and process hollowing. Malicious browser extensions posing as AI assistants, including a fake Perplexity extension with 10,000 installs, acted as infostealers. In one case, attackers used a Claude coding agent to develop a Rust remote access trojan communicating over Slack after an SQL injection compromise.

Help Net Security · 27d agoThreat actor in the wild