StegoAd Edge Extension Install Followed by Steganographic Image CDN Fetch

Ibrahim Saud@tektrix

•updated Jun 29, 2026•1•0•6

This rule detects the installation of a new Microsoft Edge extension followed by suspicious network activity from the msedge.exe process within 24 hours. The suspicious activity includes the fetching of common steganography-friendly file types (e.g., .png, .webp, .woff2, .conf) from known StegoAd C2 domains. This behavior is indicative of a malicious extension retrieving payloads hidden in legitimate-looking media files or beaconing to attacker infrastructure.