A New TrickBot module discovered brute-forcing RDP connections on selected targets, mostly the telecom industry.

TrickBot is a well-know trojan for credential-harvesting, it is active since 2016, and it’s mainly focused on stealing financial data.

TrickBot RDP Scan Module

Security researchers from Bitdefender observed the new TrickBot module (rdpScanDll) that specifically built for brute-forcing RDP connections.

Trickbot trojan primarily distributed through spam emails, also known for its aggressive network spreading capabilities.

Once the Trickbot got executed on the machine it downloads the plugin and its configuration file from the C&C server. The plugin includes a list containing servers and the set of commands to be executed.

The plugin attacks RDP connections in three different modes;

Check Mode – Checks for RDP connection on the list of targets repeatedly.

TryBrute Mode – Will perform brute force attack on the list of targeted IPs.

Brute Mode – Seems the module still in the development phase.

If the Trickbot RDP module found a host online it reports to the C&C server & main module about the status of the host and it’s working credentials.

Researchers able to find “lists contained 49 IP addresses (/rdp/domains) and 5,964 IP addresses (/rdp/over). Most of these targets are located in the United States and Hong Kong.”

The module mainly targets telecommunication industries, here is the list of affected industries

“We were able to retrieve 3,460 IP addresses, divided into 2,926
command and control servers and 556 servers dedicated to downloading new plugins, and 22 IPs serving both roles.”

The rdpScanDll is the new attachment to the TrickBot Trojan, the threat actors behind TrickBot module continues to expand its capabilities.