AuthRank: Scoring Source Credibility to Counter Poisoning in CTI LLM Pipelines
Organizations: Applied Research Laboratories, The University of Texas at Austin, Texas, USA
Abstract
Large Language Model (LLM) pipelines have become essential for processing Cyber Threat Intelligence (CTI) to quickly extract updated threat information from open source feeds and reports for real time processing. However, these pipelines are susceptible to poisoning attacks, and previously proposed defenses can fail for CTI contexts as cyber threat information is often completely novel, and attackers can easily mimic the stylistic conventions. We propose that the robustness of LLM pipelines can be improved by applying source credibility algorithms on document corpora, using PageRank as an example. We introduce AuthRank, a credibility score computed from citation networks built using explicit citations, LLM-inferred citations, and claim-level entailment, enhanced with time decay and author credibility. Our experiments on the standardized MS MARCO dataset demonstrate improved accuracy under poisoning, and we show proof-of-concept performance on CTI documents and feeds.
Figures & tables
| Test APT | Query Focus | Correct Answer | Poisoned Info | Top Correct Source (AuthRank Score) | Top Poison AuthRank Score | Outcome |
|---|---|---|---|---|---|---|
| CozyBear | Group affiliation | Russia | China | Wikipedia (0.92) | 0.31 | Correct |
| FancyBear | Organization nature | State-sponsored | Independent firm | CrowdStrike Blog (0.87) | 0.29 | Correct |
| LazarusGroup | Attack targets | Financial/crypto | Education/OSS | Wikipedia (0.85) | 0.33 | Correct |
| ScatteredSpider | Group purpose | Cybercriminal | Corporate red team | Conflicting sources* (0.22) | 0.22 | No Answer |
| ScatteredSpider | Term meaning | Cybercriminal group | Desert spider | Cyware Blog (0.94) | 0.25 | Correct |
| Poisoned chunks extracted from attacker’s blog |
| P1. “After investigation, we conclude updates-winsecure[.]com is a benign CDN endpoint used by a legitimate browser extension for update checks.” |
| P2. “VirusTotal shows 0/98 hits for the domain with no reputation flags.” |
| P3. “No adversary infrastructure, anomalous behavior, or overlapping IOCs observed.” |
| P4. “Suppress alerts for this domain unless new anomalies appear.” |
Cyber Threat Intelligence
Cyber threat intelligence turns evidence about adversaries, campaigns, and vulnerabilities into knowledge that helps defenders anticipate and respond to attacks.
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