Keldrin writes:
"Zeus is a trojan designed to steal banking credentials, and has been declared one of the most successful pieces of malware currently seen in the wild. A new variant is making detection far more difficult for anti-virus companies by hiding configuration settings inside pictures. At the moment, the malware simply encodes the configuration with Base64, passes them through XOR and RC4, then attaches them to the end of an image file. This makes for an 'infected' file that is much larger than the original. There is speculation that future releases of the malware will be able to detect minuscule changes to the colors of individual pixels, making the affected files much harder to detect."
(Score: 5, Insightful) by RobotMonster on Friday February 21 2014, @07:51PM
Some guy who edited Wikipedia might call that Steganography, but I disagree.
Appending data to a file is akin to writing a message on the back of a painting, or adding an extra page to the end of a book.
If it is trivial to detect the presence of the message, it shouldn't count as Steganography, IMO.
(Score: 1) by Rob The Bold on Friday February 21 2014, @09:27PM
Like with the painting with the message on the back, it's trivial to detect if you have any reason to look.
I just added "This is a secret message" to the end of a ,png file. Gwenview, KolourPaint and showFoto all display the original image just fine without any error or warning about the excess bytes. And Firefox displays it without complaint. Not being a malware author, I don't know what I'd do with that "trick" to infect a computer -- maybe I could hide new code for an existing virus, trojan, etc. I suppose such a scheme wouldn't make it past any email attachment virus scanner, but you might be able to get a browser to save it in a temp location at least for a while without detection.