Conventional Steganography is the old Greek craft of concealing one art in another art so well that its presence isn’t detectable by unsuspecting eye. Digital Steganography works on the same principles and hides one form of information within another kind of information. To make it easier, consider an image that will look like an image, but it may be embedded with loads of secret data which isn’t traceable.
Cryptography has had its fair share of attention, being used in both good and bad ways. The slight problem with cryptography is that, it attracts too much attention. Steganography on the other hand hides the traces that some secret message is involved, therefore does not attract attention to itself as something to be scrutinized.
While plain cryptography involves visible coded messages that arouse curiosity, Steganography is used to safely transfer conﬁdential data without arousing suspicion by concealing a ﬁle, message, image, or video within another ﬁle, message, image, or video. In countries where coding is prohibited, this digital art can be very handy for circulating secret messages.
Media ﬁles are the usual vector used for steganographic transmission of data.
For example, a plain image ﬁle can be altered in a way that the color of every 50th pixel is changed to correspond to a letter in the alphabet. The minor change will not alter the display of the image ﬁle and an unsuspecting eyeball isn’t likely to catch the steganography involved. Can you tell the difference between these two images?
A Canadian ﬁrm called Discrete Integration has a researcher who is developing advanced steganographic tools. Called Dominic Schaub, the guy says:
“[It’s] a self-concealing, perfectly deniable encryption/Steganography suite…fast, stable and functional”
Digital Steganography isn’t taking birth at the moment. It’s simply on the rise.
• Earlier in the decade, an online espionage campaign with an attack code called MiniDuke used steganography to extract command-and-control instructions from a speciﬁed Twitter account, in 2013.
• Another attack campaign sent remote control instructions for Berbomthum-infected PCs via a meme crafted from the 1999 science ﬁction ﬁlm “The Matrix”.
• The most recent application of steganography is that of malware controlled through command-containing memes posted on twitter.
• Lurk uses digital steganography to hide its URL download address and ultimately hijack infected computers to commit click fraud.
The digital art of steganography can be used for safe transfer of conﬁdential information by intelligence agencies. But why is it scary?
As mentioned above, the technique can be used to launch more sophisticated cyber-attacks. Imagine getting your whole system compromised just because you clicked on a meme. The stegano-graphed information may also remain hidden in an encrypted partition on a disk, with no traceable digital forensics. The self-concealing trait challenges cyber-crime investigators and agencies on a whole new level, making it extremely hard for them to gather digital evidence.
Describing his fool-proof masterpiece, Dominic Schaub adds:
“In this new paradigm, steganographic tools hide themselves in a self-recursive manner that renders them forensically invisible,” he says. “Moreover, upon cryptographic activation by an authorized user, these hidden tools can bootstrap themselves into existence without generating any incriminating forensic evidence. Provided that requisite cryptographic conditions are met, such steganography can be considered ‘perfectly deniable.'”
His toolkit is capable of hiding 30,000 lines of code.
Reports claim that about 90% of cyber-attacks are initiated by a spam email. Since malware can be detected by anti-malware programs, steganography can be used as another method to evade detection. Attackers may modify ﬁles and an algorithm can be developed to instruct the malware dropper to locate the modiﬁed pixels, read their machine code, and then convert that code into a URL address, using another algorithm. Once the URL address is decoded, a connection is formed and ﬁles are downloaded.
The biggest advantage/disadvantage of steganography is that, modiﬁed ﬁle wouldn’t look any diﬀerent from the original.
Even though a steganographed ﬁle looks like an exact copy of the original, embedded information can signiﬁcantly increase the size of the ﬁle. People who can lay their hands on the original ﬁle are capable of distinguishing an original ﬁle from the one containing hidden data.
To keep the data undetectable, people are replacing bits of the original ﬁle instead of adding more size to the ﬁle.
For example: The 8 bits of each byte aren’t essential to determine color of a pixel of an image. Hence, the least important bit can be replaced with one bit of code without increasing ﬁle size. Similarly, the insigniﬁcant noise in audio streams can be replaced with bits of secret data, without getting noticed.
From common man perspective, cryptography looks like a giant lock hiding a treasure, daring robbers and thieves to try it. On the other hand, steganography looks like a plain wall that hides the same treasure without demanding attention and without raising a suspecting eyebrow. Which method would you think is safer for your treasure?
Steganography seems to have endless possibilities which are currently being experimented with. Hence, it is very likely that steganography will be the new talk of the digital town, very soon.