Monikey or: the continuing evolution of Bagle

We’ve recently detected a third modification of Email-Worm.Win32.Monikey. It might seem that there’s nothing interesting about it – it spreads as an email with the subject heading «Îòêðûòêà ñ POSTCARD.RU» [A Card from POSTCARD.RU]. The body of the message contains what seems to be a link to POSTCARD.RU, but it’s actually a link to a compromised site – if the user visits this site, malicious programs will be downloaded onto his/her computer.

In itself, this isn’t very interesting. But our interest was piqued by the fact that Monikey incorporates modifications of Trojan-PSW.Win32.Vipgsm and Trojan-PSW.Win32.LdPinch.

Why is this interesting? Well, it’s yet more confirmation of our suspicions that LdPinch, Bagle, Monikey and Vipgsm are created by one and the same group of virus writers. (We wrote earlier about LdPinch and Bagle being written by the same group.) Until now, we weren’t sure that Monikey and Vipgsm were created by the same people – it was just a suspicion. Monikey contains code which is almost identical to some of Bagle’s code, but until now we thought that Monikey was simply based on Bagle’s source code, which is probably out there somewhere on the Internet.

The fact that nearly all the embedded malicious programs are encrypted using Trojan-PSW.Win32.LdPinch’s “proprietary” algorithm seems to confirm our theory. And it’s noteworthy that the latest version of Monikey appeared at the same time that the Bagle authors returned to ‘work’ after their summer vacations.

All of the above reinforces our suspicions that it’s the same people behind a number of families of malicious programs. It also confirms our prediction that the authors of Bagle would start using new approaches and technologies.

All the malicious programs have been deleted from the compromised sites, and a lot of sites have published information and apologies, stating that they did not initiate any mass mailing. However, it’s still not clear how these sites were accessed – this might have been done using passwords which were stolen using a program similar to LdPinch.

All these malicious programs have been added to Kaspersky Anti-Virus database updates.