Possible Steganography Payload in Image Download
This Suricata rule detects potential steganography payloads embedded within image downloads. It specifically looks for the JPEG file signature `FF D8 FF` within the first 3 bytes of an HTTP response, combined with a large file size (greater than 500KB). The rule also includes a threshold to prevent excessive alerts, triggering if 5 such downloads occur from the same destination within 60 seconds. This behavior is indicative of an attempt to hide malicious code or data within seemingly innocuous image files to evade detection.
Suricata
