Steganography Technologies

Understanding Steganography Technologies

Steganography is the process of hiding data in other types of data such as images or text files. The most popular method of hiding data in files is to utilize graphic images as hiding places. Attackers can embed any information in a graphic file using steganography. The hacker can hide directions on making a bomb, a secret bank account number, or answers to a test. Any text imaginable can be hidden in an image. In Exercise 4.3 you will use Image Hide to hide text within an image.

Hacking Tools ImageHide is a steganography program that hides large amounts of text in images. Even after adding bytes of data, there is no increase in the image size. The image looks the same in a normal graphics program. It loads and saves to files and therefore is able to bypass most email sniffers. Blindside is a steganography application that hides information inside BMP (bitmap) images. It's a command-line utility. MP3Stego hides information in MP3 files during the compression process. The data is compressed, encrypted, and then hidden in the MP3 bitstream. Snow is a whitespace steganography program that conceals messages in ASCII text by appending whitespace to the end of lines. Because spaces and tabs generally aren't visible in text viewers, the message is effectively hidden from casual observers. If the built-in encryption is used, the message can't be read even if it's detected. CameraShy works with Windows and Internet Explorer and lets users share censored or sensitive information stored in an ordinary GIF image. Stealth is a filtering tool for PGP files. It strips off identifying information from the header, after which the file can be used for steganography.

EXERCISE 4.3: Hiding Data in an Image Using ImageHide To hide data in an image using ImageHide: Download and install the ImageHide program. Add an image in the Image Hide program. Add text in the field at the bottom of the ImageHide screen. Hide the text within the image using ImageHide.

Steganography can be detected by some programs, although doing so is difficult. The first step in detection is to locate files with hidden text, which can be done by analyzing patterns in the images and changes to the color palette.

Countermeasure Tools Stegdetect is an automated tool for detecting steganographic content in images. It's capable of detecting different steganographic methods to embed hidden information in JPEG images. Dskprobe is a tool on the Windows 2000 installation CD. It's a low-level hard-disk scanner that can detect steganography.