Ultra stealthy spy malware not so stealthy after all

APT and the tell-tale error message

A researcher has discovered a flaw in software used to spy on government agencies and contractors that can alert security personnel that their networks have been infiltrated by the otherwise hard-to-detect programs.

The discovery by Joe Stewart, Dell SecureWorks' director of malware research, could help administrators detect so-called APT, or advanced persistent threats, such as the one revealed Tuesday that silently stalked 70 global companies, governments and non-profit organizations for as long as 28 months. While the underlying malware in these types of attacks are designed to give no clues about their presence, some of the programs broadcast error messages that are easily detected.

The error messages will continue to be viewable in organizations' network logs until the malware developers write updates that squelch the notifications. That makes it imperative that security personnel act now to capitalize on the discovery.

“For a limited time, institutions can look for signs of activity across their networks,” Stewart told The Register. “They've got a window of opportunity to check to see if they're maybe targeted as well. Trying to detect APT is hard. Any clues are good.”

The error messages are generated by tool known as HTran, which is commonly bundled with APT malware. It acts as a simplified reverse proxy server that funnels communications with a command and control channel through intermediary servers that are designed to look innocuous. When the control servers are unavailable because of network bottlenecks or other problems, some versions of HTran display error messages on the infected machine.

HTran has been in use by APT programs for years, so Stewart is guessing the tell-tale signs of infection have long been in front of researchers' noses and no one has noticed.

“I can't believe I'm the first one to see this, but I haven't seen anyone else share this information before,” he said. “We need to be doing more information sharing and trying to give each other ways to pick up this activity. Keeping this all secret isn't doing anybody any favors.” ®

Sponsored: 5 critical considerations for enterprise cloud backup