UnitedHealth subsidiary Optum hack linked to BlackCat ransomware

**Executive Summary:** A cyberattack on UnitedHealth Group subsidiary Optum disrupted the Change Healthcare payment exchange, causing widespread billing outages across U.S. hospitals, clinics, and pharmacies; forensic sources have linked the incident to the BlackCat (ALPHV) ransomware group and report exploitation of a critical ScreenConnect auth bypass (CVE-2024-1709) as an indicator of compromise, while attribution remains under investigation and some UnitedHealth systems are reported unaffected.