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    CTI-REALM: Microsoft's Detection Rule Benchmark

    CTI-REALM is Microsoft's benchmark for AI agents that turn threat intelligence into detection rules. How the CTI-REALM benchmark works and who leads it as of October 2026.

    SecurityUpdated 2026-10-30

    What It Measures

    CTI-REALM (Cyber Threat Real World Evaluation and LLM Benchmarking) is Microsoft's open-source benchmark for detection engineering, the work of turning a threat report into rules that catch the attack in real telemetry. It was published in March 2026 (arXiv 2603.13517) and mirrors what a SOC detection engineer does: read the cyber threat intelligence (CTI) report, map it to MITRE ATT&CK techniques, find the right data sources, write and test queries, and deliver a working detection.

    Of the public security benchmarks, it sits closest to a defender's daily job. A high score means the agent can carry a detection from report to deployable rule.

    How It Works

    The agent works in a sandbox with authentic attack telemetry from emulated attacks across Linux, Kubernetes (AKS) and cloud logs, plus reference databases of MITRE techniques and Sigma rules. It must produce both a Sigma rule and an executable KQL query (Kusto Query Language, used by Microsoft Sentinel and Azure Data Explorer).

    Scoring is a reward between 0 and 1 built from checkpoints along the way: deterministic checks for the techniques and data sources identified, F1 for whether the detection fires on the right events, and an LLM judge (GPT-5-Mini in the paper) for the quality of the report alignment and the Sigma rule, with a sample of judge outputs reviewed by security researchers. The benchmark is also available in the UK AI Security Institute's inspect_evals collection, so anyone can run it against a new model.

    Current Leaders

    #1

    Claude Opus 4.6 (high effort)

    Microsoft's run, same environment for all 16 configurations (Mar 2026)

    0.637
    #2

    Claude Opus 4.5

    Microsoft's run (Mar 2026)

    0.624
    #3

    Claude Sonnet 4.5

    Microsoft's run (Mar 2026)

    0.587
    #4

    GPT-5 (medium effort)

    Microsoft's run; GPT-5.2 at medium effort also scored 0.572

    0.572
    #5

    GPT-4.1

    Microsoft's run; the most token-efficient configuration, about 120,000 tokens per task

    0.419

    Which model fits which security job: Best LLM for Cybersecurity (October 2026)

    How to Interpret Scores

    Microsoft evaluated 16 model configurations, all from Anthropic and OpenAI. Claude Opus 4.6 at high reasoning effort led with a reward of 0.637, followed by Opus 4.5 at 0.624 and Sonnet 4.5 at 0.587. The best OpenAI results were GPT-5 and GPT-5.2 at medium effort, both 0.572, and GPT-4.1 scored 0.419.

    Cost per task differs as much as the score. GPT-4.1 used about 120,000 tokens per task, GPT-5 at low effort about 179,000 for a reward of 0.541, and the Anthropic models about 442,000 to 524,000. The paper also found that seeding a smaller model with workflow memory closed 33% of the gap between GPT-5-Mini and GPT-5, with the biggest gain on MITRE technique mapping, a sign that task knowledge can make up part of the gap that model size opens.

    As of 30 October 2026, no open-weight model has a published CTI-REALM result. Because the benchmark runs in inspect_evals, that gap can be closed by anyone with an open model and the telemetry environment, and it is the clearest place to test whether a right-sized open model trained for detection work can approach the frontier rows.

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