GPO-pushed ransom wallpaper via HKCU Desktop\Wallpaper UNC path

Detects multiple endpoints setting their desktop wallpaper to a common file located on a remote UNC path or containing 'sysvol'. This behavior is often indicative of GPO-based configuration for persistence or malware staging, where a malicious 'payload.jpg' is used as a cover or to deliver code via vulnerabilities in image parsing libraries.