r/ControlProblem • u/No-Conclusion3720 • 2d ago
External discussion link Anthropic warns infostealer malware is hijacking Claude sessions to drain usage
Anthropic confirmed infostealer malware is actively harvesting live Claude session tokens — not stored passwords, but authenticated sessions mid-use. Once captured, attackers impersonate the account, drain API usage, and reach anything that session can touch.
The threat model here is different from a credential breach. The session is already authenticated. Standard password hygiene and MFA don't help once the token is in attacker hands. And because AI agents operate autonomously on these sessions, a stolen session is effectively a stolen agent — one that can issue API calls, access connected data, and take actions on behalf of the legitimate user with no further authentication required.
The hard part: these sessions behave normally at the auth layer. The only signal that something is wrong is behavioral — usage patterns, geographic anomalies, request cadence — and that signal only matters if something is watching for it in real time and can act on it fast enough to matter.
For teams running AI agents in production: how are you actually handling this? Specifically curious whether anyone has meaningful runtime behavioral monitoring in place, and what your response time looks like between detection and session termination when something looks wrong.
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u/No-Conclusion3720 2d ago
The scenario here is a live session token getting siphoned and immediately reused — at that point the attacker's requests look identical to the legitimate agent's requests at the auth layer. RuntimeAI's Flow Enforcer sits in the request path and evaluates each action against a behavioral policy in real time, so when that hijacked session started issuing requests from an anomalous IP or at an anomalous cadence, the Enforcer would have evaluated that specific request, matched it against the established baseline for that non-human identity, and blocked it before the usage drain began — not after a human reviewed a log. The compromised session never gets to act. https://runtimeai.io
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u/Valkymaera approved 2d ago
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