AI Security Institute Advocates Security Best Practices After Mythos Test

The UK AI Security Institute tested Anthropic's Claude Mythos Preview and found it capable of autonomously discovering and exploiting vulnerabilities and performing multi-stage attacks in a controlled simulated corporate network (averaging 22/32 steps, with full success in 3 of 10 attempts); however, the institute cautions that the test environment lacked active defenders and other real-world protections, so real-world effectiveness is uncertain, and urges organisations to reinforce cybersecurity fundamentals and consider AI-assisted defenses.