Infostealer malware let attackers hijack Claude sessions.

Anthropic warned that attackers used infostealer malware on users’ computers to steal browser cookies and credentials, allowing them to hijack Claude login sessions and consume account usage. The company said it detected the misuse, signed out compromised sessions, removed saved payment methods and refunded unauthorized charges. Malware families such as Vidar, Lumma, StealC, RedLine, Acreed and Atomic Stealer were involved, arriving through unofficial downloads and silently harvesting stored passwords and app logins. Anthropic believes threat actors sifted through stolen data to select Claude sessions for unauthorized access, and it may continue signing users out if further misuse appears. Affected users were told to clean their systems before re‑adding payment methods.

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https://www.securityweek.com/anthropic-warns-claude-users-of-infostealer-malware-infections/