"Any time we see a leak of this nature, it's a bit of a double-edged sword," says Ken Pickering, director of engineering at CORE Security. "It gives us unique insight into how malware writers are currently targeting end users, which is exceptionally useful. At the same time, it also elevates the overall 'cybercrime' community's level of sophistication, since it gives them another example of a fairly successful piece of malicious code."
"If it's rapidly distributed," he adds, "I think we've already seen a trend of Trojan clones being released, [so] I wouldn't expect Carberp to be any different."
In 2011, another piece of financial malware had its source code leaked on the Internet -- the infamous ZeuS Trojan. It is believed by security researchers that the source code was used as the foundation for the Citadel Trojan, which was at the center of a recent takedown operation launched by Microsoft, the FBI, and others.
The source code for SpyEye was also leaked in 2011. In May, a man accused of helping to develop and spread SpyEye was extradited to the U.S. to face hacking charges. According to authorities, between 2009 and 2011 Algerian national Hamza Bendelladj -- also known as 'Bx1' -- and others developed, marketed, and sold versions of SpyEye and its component parts on the Web and allowed cybercriminals to customize their purchases.
"When ranking financial malware in terms of capabilities, Carberp is among the leaders with Zeus, SpyEye, Citadel, and all the other major financial malware," says Etay Maor, fraud prevention solutions manager at Trusteer. "Carberp source code includes all the well-known MitB [man-in-the-browser] capabilities, such as HTML injection, VNC [virtual network computing], and different forms of grabbers. In addition, the code includes a bootkit, which helps the malware stay undetected and tough to remove.
"Regardless of the leak, malware code writers are always developing new capabilities and techniques," he adds. "This may affect the pricing of malware -- as there is major malware out there for free -- and, ultimately, we might see Carberp variant sellers; however, the competition between developers never stops. An example of such a competition is highlighted in cases where sophisticated malware knows how to remove other malware from infected devices, therefore, becoming the sole owners of the stolen data."
According to Peter Kruse of CSIS Security in Denmark, the package of leaked code includes the Carberp bootkit, along with other source codes for what seems to be the Stoned bootkit, Citadel, and Ursnif.
"We also found several text files containing apparently private chats and various usernames and passwords for several FTP servers," blogs Kruse, adding that -- as was the case with the leakage of the ZeuS source code -- this means cybercriminals "have every chance to modify and even add new features to the kit."
For researchers, there is the potential plus that the leak will allow them to get better insight into what black hat hackers are up to, says Sean Bodmer, chief researcher at CounterTack.
"Not only was the Carberp code revealed in that .rar, there was also a large amount of Russian banking application code for the BSS thick client, likely exfiltrated from that organization directly," he explains. "Additionally, there are many other source compilations from bootkit techniques to anti-AV modules, which quickly become a security researcher's goldmine."
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