ESET Research discovers CDRThief, malware attacking Chinese VoIP platform
ESET researchers have discovered and analyzed malware that targets Voice over IP (VoIP) softswitches. This new malware, named CDRThief by ESET, is designed to target a very specific VoIP platform used by two China-made softswitches (software switches): Linknat VOS2009 and VOS3000. A softswitch is a core element of a VoIP network that provides call control, billing, and management. These softswitches are software-based solutions that run on standard Linux servers. Entirely new Linux malware is rarely seen, thus making CDRThief worthy of interest. The primary goal of the malware is to exfiltrate various private data, including call detail records (CDR), from a compromised softswitch.
“It’s hard to know the ultimate goal of attackers who use this malware. However, since it exfiltrates sensitive information, including call metadata, it seems reasonable to assume that the malware is used for cyberespionage. Another possible goal for attackers using this malware is VoIP fraud. Since the attackers obtain information about the activity of VoIP softswitches and their gateways, this information could be used to perform International Revenue Share Fraud,” says ESET researcher Anton Cherepanov, who discovered CDRThief. “CDRs contain metadata about VoIP calls such as caller and IP addresses of call recipients, starting time of the call, call duration, call fees, and other information,” he adds.