DARPA AI Cyber Challenge (AIxCC)

PatchBench, from the University of Maryland's AI Security Lab, evaluates 11 patching agents, including the top three AIxCC systems, on 213 C/C++ tasks whose true fixes lie outside the crash stack, using vulnerability transplant and code mutation to limit memorization. It finds that accepting a patch because the original proof-of-concept no longer crashes inflates solve rates by 1.83x on average, and that about 25% of agent patches closely resemble historical developer fixes.

A systematization-of-knowledge paper by organizers and competitors analyzes AIxCC's design, the seven finalist architectures and results beyond the scoreboard. It reports that system stability and accuracy penalties decided rankings, that LLM-based systems found vulnerabilities a fuzzing baseline missed, and that among patches passing all automatic validation, manual review found semantic errors in 38-46% from baseline agents; the top two systems had 83.8% and 79.2% competition-scored patch accuracy.

DARPA reports that seven finalist cyber reasoning systems analyzed over 54 million lines of code, found 54 unique synthetic vulnerabilities in 63 challenges and patched 43, and found 18 real non-synthetic vulnerabilities with 11 patches. Team Atlanta won $4 million, Trail of Bits $3 million and Theori $1.5 million; DARPA and ARPA-H added $1.4 million for real-world integration and four systems were open-sourced on the day.

DARPA reports that in the AIxCC semifinal at DEF CON 32, nearly 40 cyber reasoning systems were tested on challenge projects based on Jenkins, the Linux kernel, Nginx, SQLite3 and Apache Tika. Competitors' systems found 22 unique synthetic vulnerabilities, patched 15, and found one real-world SQLite3 bug; seven teams advanced with $2 million each and must open-source their systems after the final.

At Black Hat USA 2023, DARPA announced the AI Cyber Challenge (AIxCC), a two-year competition to build AI-driven systems that automatically find and fix vulnerabilities in critical open-source software. Anthropic, Google, Microsoft and OpenAI agreed to provide technology and expertise to competitors, OpenSSF served as challenge advisor, and semifinal and final rounds were scheduled for DEF CON 2024 and 2025.