US authorities dealt a significant blow to the most successful computer crime organisation this week, but it's unclear whether the masterminds behind the Zeus malware will ever be brought to justice.
On Thursday federal and local authorities in New York announced charges against 92 people thought to be responsible for online attacks against consumers, small businesses and other organizations that resulted in more than US$200 million in stolen money over the past four years. The action follows a Tuesday raid in the UK that led to 20 arrests.
Seventy-three people were charged Thursday by federal and New York state authorities. Of those, 19 had previously been charged with related crimes, according to a spokeswoman with the Manhattan District Attorney's Office.
The arrests are part of an international effort to bring an end to one of today's worst computer crime problems: the Zeus Trojan. First spotted in 2006, Zeus has evolved into a decentralized, worldwide criminal enterprise that has been a bane to banks and IT administrators alike. It has cast an unsavory light on the dark side of the Internet revolution, preying unmercifully on small businesses and organizations that are least able to defend themselves from well-organized online attacks.
It's had an effect on large organizations too, sucking up valuable IT resources.
Until he left his job in computer incident response at a large federal agency three months ago, fighting Zeus was part of Dan Guido's daily life. "Ninety percent of my time was spent dealing with banking Trojans that were delivered to Windows desktop clients, " Guido said. "Probably 75 percent of that time it was Zeus."
Victims get hit when Zeus' authors trick them into visiting a malicious website that is loaded with Web-based attacks. If their Web browser or one of its plug-in components is out-of-date, the victim gets infected. Antivirus software does little to help, because the criminals are adept at tweaking their code to evade detection.
Guido, a security consultant who asked that his former employer not be identified, believes that most other large organizations are probably in the same boat.
Once the Zeus software is installed on the desktop, it uses a variety of sneaky techniques to log into the victim's bank account and set up a balance transfer, using what's known as the ACH (Automated Clearing House) system. ACH transfers are very easy to set up, and many banks do not impose the proper controls to prevent criminals from moving money without the knowledge of bank account holders.
In one case, criminals siphoned more than $700,000 from Pennsylvania's Western Beaver County School District over the Christmas holidays by adding payees to the district's bank account using ACH. By the time the school got its bank to reverse the funds, more than $441,000 had been moved offshore.
Western Beaver ended up suing its bank, but many ACH fraud cases are quietly settled out of court, keeping the phenomenon out of the public eye.
Thursday's charges, brought by both the U.S. Department of Justice and the Manhattan District Attorney's Office, deal a grave blow to the money mule system that the Zeus criminals had set up to move cash out of the U.S., but it doesn't touch the people who developed the code, run the back-end servers, and generally set up the scam in the first place.
The U.S. Federal Bureau of Investigation acknowledged Thursday that there is still more work to go. "It remains an ongoing investigation," said FBI spokesman Paul Bresson.
Zeus's main software developer, who once went by the name A-Z, is thought to live in St Petersburg, according to Don Jackson, a researcher with SecureWorks, one of the companies that has been tracking Zeus for years.
To complicate matters, Zeus is not run by a single gang. There are perhaps five to 10 Zeus gangs that operate at the highest level, Jackson said. These are the crooks who get access to the best code, who have the most up-to-date attacks, and who make the most money.
However the Zeus code is also freely sold on the black market, and there are many others who also make their own use of the malware.
That means that Zeus is not going away any time soon. And unless authorities in the Eastern European countries that are Zeus' home also make arrests, it could easily re-emerge as a problem in the U.S.
"I don't even think that we're going to see Zeus necessarily stop," said Zeus expert Gary Warner, the director of research in computer forensics with the University of Alabama at Birmingham. "This particular family of Zeus has probably seen the end of its days, but something will step into the void."