Autostart Payload Delivered as Startup Script
This rule detects the delivery of a potential autostart payload as a startup script over HTTP. It looks for HTTP URIs containing keywords like 'startup', 'autostart', or 'autorun' (case-insensitive) and checks the file data for the 'MZ' header, indicating an executable file, within the first 2 bytes of the file content. This combination suggests an attempt to deliver an executable that could be configured for persistence.
Suricata

