Not every security investigation starts with an alert from a SIEM or an endpoint detection platform. Sometimes, the first useful clue is already available in public sources. A company website may reveal technology information. A forgotten subdomain can expose an overlooked asset. Public code repositories may contain valuable technical context. Social platforms, breach reporting, domain records, and other open sources can help security professionals understand an organization's external footprint. This is where OSINT cyber security becomes important. Visit: https://cyberwarfare.live/certifications/offensive-osint-operator-co3/ Web 2.0: https://justinsimpsonedu.wixsite.com/learn-cyber-security/post/osint-cyber-security-turning-open-source-data-into-security-intelligence