Cathedral’s agents broke into Anthropic in under 12 hours

Security start-up Cathedral’s AI agents reached Anthropic’s Slack messages and salary details in under 12 hours, per a draft report reviewed by The Washington Post. Anthropic confirmed access to a limited set of sales, HR and IT systems, but said customer chats with Claude, source code and model weights stayed out of reach.

The agents went through business software Anthropic uses for admin and sales, in a test under its outside-researcher program. Anthropic said it cut off access the same day after its monitoring flagged some of the activity.

Anthropic says Cathedral broke the program’s rules by not disclosing all its activity. Cathedral says it kept data access to the minimum.