Paper Detail

Beyond Success Rate: Cost-Aware Evaluation of Offensive and Defensive Security Agents

Paul Kassianik, Blaine Nelson, Yaron Singer

arxiv Score 18.2

Published 2026-07-16 · First seen 2026-07-17

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Abstract

Security-agent evaluations commonly measure peak offensive capability under generous inference budgets, emphasizing vulnerability discovery, exploit development, penetration testing, and CTF completion. Such measurements are useful but incomplete: in operational security, every reasoning step, tool call, telemetry query, and enrichment request consumes budget. We evaluate language-model security agents through this cost-success lens on offensive Cybench challenges and defensive Splunk BOTS v1 investigation challenges. Instead of reporting only best-case success, we compare models at fixed cost levels and decompose performance by inference spend and tool spend. Our results show distinct scalingregimes for red- and blue-team tasks. Offensive CTF performance improves with additional test-time compute, and scaled open-weight models can approach frontier proprietary systems while remaining cost-competitive. Defensive SOC investigation does not scale in the same way: success depends more heavily on disciplined tool use, telemetry navigation, and selective enrichment than on raw reasoning budget alone. We argue that security-agent benchmarks should measure economic efficiency and operational fit alongside task success. Cost-aware, SOC-native evaluations provide a clearer picture of which models are practically useful today and where defensive agents still need to improve. We present an interactive website with our results https://evals.frontier.security.

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BibTeX

@article{kassianik2026beyond,
  title = {Beyond Success Rate: Cost-Aware Evaluation of Offensive and Defensive Security Agents},
  author = {Paul Kassianik and Blaine Nelson and Yaron Singer},
  year = {2026},
  abstract = {Security-agent evaluations commonly measure peak offensive capability under generous inference budgets, emphasizing vulnerability discovery, exploit development, penetration testing, and CTF completion. Such measurements are useful but incomplete: in operational security, every reasoning step, tool call, telemetry query, and enrichment request consumes budget. We evaluate language-model security agents through this cost-success lens on offensive Cybench challenges and defensive Splunk BOTS v1 in},
  url = {https://arxiv.org/abs/2607.15263},
  keywords = {cs.CR, cs.AI},
  eprint = {2607.15263},
  archiveprefix = {arXiv},
}

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