How OSINT is Used in Cybersecurity (Real-World Use Cases)

This article demonstrates how open-source intelligence (OSINT) is used in cybersecurity through multiple real-world cases: investigator-driven APT profiling and infrastructure tracking (APT41, Volt Typhoon), massive credential exposures (public Elasticsearch instances with ~9.8B records), supply-chain compromise detection (XZ Utils backdoor, Polyfill.io), large phishing campaigns (0ktapus/Scattered Spider) and ransomware attribution/response (MOVEit/Cl0p, LockBit). It highlights defender techniques—certificate transparency monitoring, JARM/TLS fingerprinting, registrar and hosting pivots, and public code/repository forensics—and argues that public data is a critical reconnaissance and defensive resource.