Trojans in Artificial Intelligence (TrojAI) Final Report
Authors:
Kristopher W. Reese,
Taylor Kulp-McDowall,
Michael Majurski,
Tim Blattner,
Derek Juba,
Peter Bajcsy,
Antonio Cardone,
Philippe Dessauw,
Alden Dima,
Anthony J. Kearsley,
Melinda Kleczynski,
Joel Vasanth,
Walid Keyrouz,
Chace Ashcraft,
Neil Fendley,
Ted Staley,
Trevor Stout,
Josh Carney,
Greg Canal,
Will Redman,
Aurora Schmidt,
Cameron Hickert,
William Paul,
Jared Markowitz,
Nathan Drenkow
, et al. (46 additional authors not shown)
Abstract:
The Intelligence Advanced Research Projects Activity (IARPA) launched the TrojAI program to confront an emerging vulnerability in modern artificial intelligence: the threat of AI Trojans. These AI trojans are malicious, hidden backdoors intentionally embedded within an AI model that can cause a system to fail in unexpected ways, or allow a malicious actor to hijack the AI model at will. This multi…
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The Intelligence Advanced Research Projects Activity (IARPA) launched the TrojAI program to confront an emerging vulnerability in modern artificial intelligence: the threat of AI Trojans. These AI trojans are malicious, hidden backdoors intentionally embedded within an AI model that can cause a system to fail in unexpected ways, or allow a malicious actor to hijack the AI model at will. This multi-year initiative helped to map out the complex nature of the threat, pioneered foundational detection methods, and identified unsolved challenges that require ongoing attention by the burgeoning AI security field. This report synthesizes the program's key findings, including methodologies for detection through weight analysis and trigger inversion, as well as approaches for mitigating Trojan risks in deployed models. Comprehensive test and evaluation results highlight detector performance, sensitivity, and the prevalence of "natural" Trojans. The report concludes with lessons learned and recommendations for advancing AI security research.
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Submitted 27 February, 2026; v1 submitted 6 February, 2026;
originally announced February 2026.