Infostealers are hijacking Claude accounts at users’ expense

Anthropic has warned some Claude users that criminals are using information stealers to take over their accounts. Rather than guessing passwords or intercepting two-factor authentication (2FA) codes, the attackers steal the browser sessions that prove a user is already logged in. According to a warning email shared publicly by an affected user, the attackers used common infostealer malware to copy Claude login sessions from victims’ computers.