A Plausible Task Can Serve an Unauthorised Objective
Anthropic described reconnaissance, vulnerability discovery, exploit development, credential harvesting, data analysis and exfiltration across the reported campaign. It said the attackers used multiple Claude Code instances and had the system produce documentation of stolen credentials and analysed systems.
The headline number needs restraint. An estimate that AI performed 80–90% of the work does not mean that humans disappeared or that every target experienced every stage. Target selection and other consequential decisions remained human. The report also said the model sometimes overstated results, requiring the operators to validate its output.
The useful control problem is cumulative authority. An agent may be permitted to scan a system. It may be permitted to analyse records. It may even be permitted to prepare code. Those individual permissions do not authorise it to connect the results into an intrusion and move data elsewhere.
Disrupting the first reported AI-orchestrated cyber espionage campaign: The Anthropic account is very readable and well worth your time
Prompt screening examines one transaction. Agent security also has to examine the journey: the declared purpose, delegated tasks, expanding access, new destinations and final effect.