Steganalysis is the art of finding secret data hidden inside normal-looking files - like a message tucked into a photo, song, or video. Unlike cryptography (which scrambles data), steganography tries to hide that data so nobody notices it’s there; steganalysis is how we spot and prove that hiding.
Criminals and some malware hide commands, keys, or stolen info inside everyday media to dodge filters. Being able to detect that trick helps stop data leaks, catch covert channels, and support digital forensics.
File format checks: look for odd headers, sizes, or extra chunks that don’t belong.
Content checks: compare an image’s pixels or an audio’s waveforms for tiny “off” patterns.
Statistics: run math tests to see if noise looks too perfect or too weird.
Tool-specific tells: scan for fingerprints left by popular stego tools or known malware methods.
Media files that are much larger than expected (e.g., tiny photo with giant file size).
Files that break when resized, re-encoded, or lightly edited.
Repeated downloads of “stock” images from unusual servers.
Unexpected media attachments in places where text would be normal.
Keep suspicious media in a lab folder and copy it before testing.
Re-encode or resize a copy - if hidden data is present, it often breaks.
Use multiple scanners (hash tools, metadata viewers, stego detectors) and keep notes.
If this is part of an incident, preserve originals and involve your security/forensics team.