APT to Disagree: A Comparative Analysis of Attribution in Commercial TI

Attributed cyber threat intelligence (TI) plays an important role in the effective mitigation of cyber attacks. Yet, despite the central role of attribution in policy, practice, and vendor reporting, little is known about the coverage and reliability of attribution by threat intelligence vendors. No study has systematically investigated attribution across a large set of leading TI vendors. We close this gap and provide a longitudinal comparative analysis across $\mathbf{1 3. 5}$ million IOCs collected over the last 14 years from seven vendors. To compare IOC attribution across vendors, we normalize heterogeneous feeds and reconcile actor names using an evaluated and augmented version of MISP Threat Actor Galaxy (MISP TAG). Next, we address two questions: (i) what is the scope of actor-tracking by vendors, and (ii) how consistent is attribution among vendors? We find that the majority of actors tracked by one vendor are not tracked by the other. Furthermore, IOCs observed by multiple TI vendors are rare (1 %), illustrating that commercial TI feeds, like open-source feeds, primarily provide singleton IOCs. We also find limited overlap in IOCs for jointly tracked actors by two vendors. We measure attribution agreement among vendors with Krippendorff's $\alpha$. We find mostly moderate agreement among vendors for actor attribution. By contrast, country attribution has high agreement. Our results have implications for actor-centric defenses, compliance, and geopolitical uses of attribution.