Despite the billions of dollars invested in the threat intelligence (TI) ecosystem—a globally distributed network of security vendors and altruists who drive critical cybersecurity operations—we lack an understanding of how it functions, including its dynamics and vulnerabilities. To fill that void, we propose a novel measurement framework that tracks binaries as they traverse the ecosystem by monitoring for watermarke network Indicators of Compromise (IoCs). By analyzing each stage of the propagation chain of submitted TI (submission, extraction, sharing, and disruption), we uncover an ecosystem where dissemination almost always leads to the disruption of threats, but vendors who selectively share the TI they extract limit the ecosystem’s utility. Further, we find that attempts to curtail threats are often slowed by ‘bottleneck’ vendors delaying the sharing of TI by hours to days.

Critically, we identify several threats to the ecosystem’s supply chain, some of which are presently exploited in the wild. Unnecessary active probing by vendors, shallow extraction of dropped files, and easy-to-predict sandbox environment fingerprints all threaten the health of the ecosystem. To address these issues, we provide actionable recommendations for vendors and practitioners that improve the safety of the TI supply chain, including detection signatures for known abuse patterns. We collaborated with vendors through a responsible disclosure process, gaining insight into the operational constraints underlying these weaknesses. Finally, we provide a set of ethical best practices for researchers actively measuring the threat intelligence ecosystem.