The cybercrime underground is expanding each day, yet the longer I study it the more convinced I am that much of it is run by a fairly small and loose-knit group of hackers. That suspicion was reinforced this week when I discovered that the author of the infamous ZeuS Trojan was a core member of Spamdot, until recently the most exclusive online forum for spammers and the shady businessmen who support the big spam botnets.
Thanks to a deep-seated enmity between the owners of two of the largest spam affiliate programs, the database for Spamdot was leaked to a handful of investigators and researchers, including KrebsOnSecurity. The forum includes all members’ public posts and private messages — even those that members thought had been deleted. I’ve been poring over those private messages in an effort to map alliances and to learn more about the individuals behind the top spam botnets.
As I was reviewing the private messages of a Spamdot member nicknamed “Umbro,” I noticed that he gave a few key members his private instant message address, the jabber account email@example.com. In 2010, I learned from multiple reliable sources that for several months, this account was used exclusively by the ZeuS author to communicate with new and existing customers. When I dug deeper into Umbro’s private messages, I found several from other Spamdot members who were seeking updates to their ZeuS botnets. In messages from 2009 to a Spamdot member named “Russso,” Umbro declares flatly, “hi, I’m the author of Zeus.”
Umbro’s public and private Spamdot postings offer a fascinating vantage point for peering into an intensely competitive and jealously guarded environment in which members feed off of each others’ successes and failures. The messages also provide a virtual black book of customers who purchased the ZeuS bot code.
In the screen shot above, the ZeuS author can be seen selling surplus “installs,” offering to rent hacked machines that fellow forum members can seed with their own spam bots (I have added a translation beneath each line). His price is $60 per 1,000 compromised systems. This is a very reasonable fee and is in line with rates charged by more organized pay-per-install businesses that also tend to stuff host PCs with so much other malware that customers who have paid to load their bots on those machines soon find them unstable or unusable. Other members apparently recognized it as a bargain as well, and he quickly received messages from a number of interested takers.
The image below shows the Zeus author parceling out a small but potentially valuable spam resource that was no doubt harvested from systems compromised by his Trojan. In this solicitation, dated Jan. 2008, Umbro is selling a mailing list that would be especially useful for targeted email malware campaigns.