Anonymous YARA Rules Are Not Anonymous

Computer Science > Cryptography and Security [Submitted on 26 May 2026] Anonymous YARA Rules Are Not Anonymous Usman Rabiu Isah, Laurent Bobelin, Pascal Berthomé YARA rules are widely shared across threat intelligence communities to enable collective defence against malware. This practice implicitly assumes that removing metadata (e.g., author fields) sufficiently protects the identity of contributing organisations. To assess the validity of this assumption, we systematically evaluate how much can be inferred from YARA rule text alone. Specifically, using a corpus of 23,305 rules from three major public repositories, we train independent classifiers along four stylometric fingerprint dimensions: individual author, source repository, malware family, and temporal drift, using three complementary methods: lexical n-grams (Burrows' Delta), syntactic AST features (Caliskan-Islam), and fine-tuned CodeBERT. Our results demonstrate that repository origin is almost perfectly recoverable (up to 99% accuracy), individual authors can be re-identified well above chance (76%), and malware family classification reaches 95%. Comparing the same repository attribution task across full-history and time-restricted subsets reveals a 9-18% accuracy gap, providing preliminary evidence of temporal drift in repository this http URL further disentangle content from style, we conduct per-malware family author attribution experiments. Even when the malware family is the same for all samples considered, authors can still be re-identified for five of seven tested families (mean accuracy 74.6%). These findings constitute the first systematic demonstration that YARA rule sharing is a measurable OPSEC attack surface, and that metadata removal alone does not mitigate it. Subjects: Cryptography and Security (cs.CR) Cite as: arXiv:2605.26791 [cs.CR]   (or arXiv:2605.26791v1 [cs.CR] for this version)   https://doi.org/10.48550/arXiv.2605.26791 Focus to learn more Submission history From: Laurent Bobelin [view email] [v1] Tue, 26 May 2026 10:01:50 UTC (548 KB) Access Paper: HTML (experimental) view license Current browse context: cs.CR < prev   |   next > new | recent | 2026-05 Change to browse by: cs References & Citations NASA ADS Google Scholar Semantic Scholar Export BibTeX Citation Bookmark Bibliographic Tools Bibliographic and Citation Tools Bibliographic Explorer Toggle Bibliographic Explorer (What is the Explorer?) Connected Papers Toggle Connected Papers (What is Connected Papers?) Litmaps Toggle Litmaps (What is Litmaps?) scite.ai Toggle scite Smart Citations (What are Smart Citations?) Code, Data, Media Demos Related Papers About arXivLabs Which authors of this paper are endorsers? | Disable MathJax (What is MathJax?)