Trojanized Software Update Download

Darshan Thummar@Mighty

•updated Jun 11, 2026•0•0•1

This rule detects the download of potentially trojanized software updates. It specifically looks for HTTP traffic flowing to the client, where the URI contains "update" (case-insensitive), the HTTP host contains "update.", "cdn.", or "download." (case-insensitive), and the file data starts with "MZ" (indicating a Windows executable) within the first 2 bytes. Additionally, the downloaded file size must be greater than 500,000 bytes.