A Dyre New Banking Trojan

Creators of a newly discovered Remote Access Trojan (RAT) strain that's targeting customers of a number of major banks could become another fixture in the crime-as-a-service ecosystem. Initially uncovered by security researchers at PhishMe, the Dyre or Dyreza Trojan at the moment appears to be the first of a new family of Trojan rather than a Zeus retread. It was picked up by researchers as they looked into an ongoing Dropbox phishing campaign.

"When analyzing tools, tactics, and procedures for different malware campaigns, we normally don’t see huge changes on the attackers’ part," wrote Ronnie Tokazowski, senior researcher for PhishMe. "However, in the Dropbox campaign we have been following, not only have the attackers shifted to a new delivery domain, but they have started to use a new malware strain, previously undocumented by the industry."

According to Peter Kruse, partner and security specialist for CSIS Security Group, like many RATs on the black market, Dyreza is designed specifically to attack online banking customers.

"The target list has a specified set of targets which whenever visited will trigger some additional functions in the Trojan and harvest credentials," he told Dark Reading.

CSIS found that targeted institutions included Bank of America, Natwest, Citibank, RBS, and Ulsterbank. And PhishMe reports that the malware effectively bypasses SSL protections within the browser while stealing credentials. Through its research, CSIS also reported today a key piece of evidence that shows the malware is looking to make a splash of its own compared to Zeus. "The group behind Dyreza has implemented their own money mule panel which indicates that they intend to provide this as a crime-as-a-service solution or is a full circle in-house crime gang."

Unlike Zeus, the malware also currently doesn't appear to have advanced capabilities such as data encryption, many-to-one relationships with command and control infrastructure, or randomization of file names, Tokazowski told Dark Reading.

"One of the biggest differences between ZeuS and Dyre is how communication with the command-and-control infrastructure takes place. With ZeuS, data is usually encoded or encrypted, then passed back as raw binary data. With Dyre, the data is POSTed in the clear, making detection for enterprises with IDS capabilities very straightforward," Tokazowski says. "Since data is being posted back unencrypted, I believe this malware is only in its infancy, and we should expect more refinements from the malware author."

According to Tokazowski, given the lack of Zeus-like features and differences in network communication, there's a good chance the malware is based on a new code base. This is the second time in two weeks that researchers have claimed to have found new banking Trojan strains. Last week RSA reported the same about malware it called Pandemiya, though Kruse of CSIS claims that analysis by the security community has shown that it may have reused code from Gozi.

Tokazowski postulated that a new rash of RATs could be coming as a result of the recent GoZeus takedown.

"With the takedown of GoZeus, the crimeware community will need a new RAT with different capabilities, and I expect to see more RATs in the future with one malware variant stepping in to fill the void left by GoZeus," he says.

While Kruse agrees, he warns that practitioners shouldn't count GoZeus out just yet.

"Remember that ZeuSP2P/Gameover has been taken over and have not as such been eliminated. The malware is like a flu," he says. "We have dismantled its capabilities to push new updates and helped remove the threat from already infected machines, but that does not mean that the gang behind GoZeuS won’t start infecting new users through spam campaigns and Pay Per Installs."