Data Hiding/Embedding

File Format
Name	Data Hiding/Embedding
Ontology	Electronic File Formats Encryption Data Hiding/Embedding

Steganography tries to remain hidden even if you're looking for it while data hiding/embedding is a more crude approach that relies on not being noticed/looked for in the first place.

JPEG

There are two main approaches to embedding data in a JPEG file: using the EXIF headers or appending it after the end of image marker (FF D9)

A common tactic is to manually append a zip/rar file to the end of a JPEG. The resulting file will still open as a regular JPEG in any image program, but any archiver will automatically detect and open zip/rar part.

In DOS/Windows command line, files can be appended by using the command:
copy /b host.jpg + hidden.zip combined.jpg

In Linux/Mac the command looks like:
$ cat host.jpg hidden.zip > combined.jpg

• Under the hood: Hiding data in JPEG images
• Malware Hidden Inside JPG EXIF Headers
• GG-AESY - implements both methods of hiding data