We have been tracking RDAT since 2017, when we first saw this tool uploaded to a webshell related to the TwoFace webshell discussed in our Striking Oil blog published on September 26, 2017. RDAT has been under active development since 2017, resulting in multiple variations of the tool that rely on both HTTP and DNS tunneling for C2 communications. In June 2018, the developer of RDAT added the ability to use Exchange Web Services (EWS) to send and receive emails for C2 communications. This email-based C2 channel is novel in its design, as it relies on steganography to hide commands and exfiltrates data within BMP images attached to the emails. The combination of using emails with steganographic images to carry the data across the C2 can result in this activity being much more difficult to detect and allow for higher chances of defense evasion