Cotx RAT
Description
(Proofpoint) The RasTls.dll contains the Cotx RAT code. The malware is written in C++ using object-oriented programming. We named it by borrowing the name of the location of its stored configuration. The encrypted configuration is stored in the side-loaded DLL file RasTls.dll in a PE section named “.cotx”. The current encrypted configuration is also stored in the registry key “HKEY_LOCAL_MACHINE\SOFTWARE\Intel\Java\user”.
The command and control structure of Cotx RAT is proxy aware. It utilizes wolfSSL for TLS encrypted communication. The initial beacon contains “|”-delimited system information. The data included in the beacon is Zlib compressed and encrypted with AES-192 in CBC mode utilizing the same keys as the configuration. The following values are included:
• ‘id’ value from ‘software\intel\java’ subkey • Computer name • ‘mark’ field from configuration • Username • Windows version • Architecture • Possible malware version. ‘0.9.7’ is hardcoded in the analyzed sample • Local IP addresses • First adapter’s MAC address • Connection type (https or _proxy) • ‘password’ field from configuration
Names
| Name |
|---|
| Cotx RAT |
Category
Malware
Type
- Reconnaissance
- Backdoor
- Credential stealer
Information
Malpedia
Other Information
Uuid
071fed27-3361-4b37-a553-8e32c65482c8
Last Card Change
2021-04-24