Researchers have shut down a network of PCs responsible for sending out 200 million spam messages, claiming to support US presidential candidate Ron Paul last month.
After analysing the server's software, it has become clear that there is no such thing as a 'Ron Paul botnet', according to Joe Stewart, a senior security researcher with SecureWorks.
"It probably wasn't even set up by a Ron Paul supporter," he said. "This whole system has been around since 2004. This [spam] somehow just landed in this underground spam economy."
When spam first surfaced, trumpeting Paul as the winner of a recent Republican presidential debate, the fact that it was being sent via illegally infected machines raised eyebrows.
The spam messages have never been directly linked to the Ron Paul campaign, which has denied any involvement in the incident.
The Texas congressman is considered a long-shot contender for the Republican presidential nomination, but he has a strong internet presence. His videos are popular on YouTube, and Ron Paul fundraisers recently were able to raise more than $4m in a 24-hour period.
Stewart published an analysis of the botnet on Tuesday, connecting it to an Eastern European spammer known as "spm", whose company, Elphisoft, sends unsolicited email using a network of about 3,000 infected botnet PCs. Stewart believes that spm, and many of the people involved in his operation, are located in the Ukraine.
The botnet server used to manage the Ron Paul spam was located in the US and shut down in mid-November, giving researchers a chance to examine the software on the machine, Stewart explained.
Apparently spm rented out his botnet to a middleman, a spammer calling himself "nenastnyj", who has also sent out messages promoting pornography, online gambling, and male enhancement technology. He probably paid spm between $100 and $1,000 to send out the Ron Paul mailing, Stewart said.
It is nearly impossible to figure out who nenastnyj really is, but Stewart made a few guesses, based on his previous spam jobs stored on the server. "Nenastnyj appears just to be a small-time spammer who doesn't write the spam software," he said. "Basically he just makes money by finding sponsors and then becoming a mailer for them and using someone else's mail service to send it."
This botnet is one of 16 controlled by spm's servers, which use a user-friendly, web-based application called Reactor Mailer to manage spam mailings. "The interface is pretty slick; it's Web 2.0-enabled," Stewart said. "It shows that they really do view this as a business and they put out a quality product. They are trying to make a lot of money on this."
The spammers used a malicious Trojan horse program called Trojan.Srizbi to take control of computers and link them into the botnet.