Tendrit is a backdoor malware family that has been used in targeted attacks since 2011. The malware is known to spread through phishing campaigns that use holiday themes to lure the victims into running their payload. In this blog post we will discuss how to detect its beaconing activity using RSA Security Analytics.
Once it infects a victim machine, this Tendrit variant start to collect data about the victim machine like its hostname, username, MAC address and OS version. The collected data is encoded and sent to the C2 server via a GET request as shown in the screenshot below:
The network behavior is the same across Tendrit samples:
Assuming the appropriate meta keys are enabled, the following query can be used to detect Tendrit network activity:
service = 80 && action = 'get' && filename = 'css.ashx' && query begins 'nly='
Scan results for a Tendrit variant can be viewed here.