Level 6
Malware researchers discovered a new threat that they named CDRThief targeting a specific Voice over IP system to steal call data records (CDR) from telephone exchange equipment.

Analysis of the malware revealed that it was specifically created for a particular Linux VoIP platform, namely Linknat VOS2009/3000 softswitches.

Clear purpose
A softswitch is a software solution acting as a VoIP server that manages traffic (audio/video/text) in a telecommunication network. It is a central element that ensures a connection between both internal and external lines.


Level 64
Content Creator
Malware Hunter
We analyzed Linux/CDRThief malware, which has a unique purpose to target specific VoIP softswitches. We rarely see VoIP softswitches targeted by threat actors; this makes the Linux/CDRThief malware interesting.

It’s hard to know the ultimate goal of attackers who use this malware. However, since this malware 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 activity of VoIP softswitches and their gateways, this information could be used to perform International Revenue Share Fraud (IRSF).