According to CoinMeta, Anthropic is sending security warnings to some Claude users because hackers have stolen Claude login sessions through computers infected with malware, thereby consuming the users' quotas. Users shared the warning emails they received on Reddit. The emails indicate that attackers obtained the logged-in sessions in the browsers, not the passwords, and that users may still be at risk even if they have enabled two-factor authentication. Anthropic lists various types of Trojans that steal relevant information, including those on Windows such as Vidar, Lummac2, Stealc, Redline, Acreed, as well as on Mac like Atomic Stealer ( AMOS ). The company has canceled the abnormal login sessions detected and removed the payment methods saved in the accounts, reminding users that simply changing passwords will not solve the problem; it is necessary to remove the malware from their computers.