Threat description



Breplibot.C is a backdoor with bot capabilities. It connects to several IRC servers and waits for commands from the backdoor author. The backdoor tries to utilize Sony DRM software for hiding its process, file and registry keys. More information about Sony DRM can be found here:


Automatic action

Depending on the settings of your F-Secure security product, it will either automatically delete, quarantine or rename the suspect file, or ask you for a desired action.

More scanning & removal options

More information on the scanning and removal options available in your F-Secure product can be found in the Help Center.

You may also refer to the Knowledge Base on the F-Secure Community site for more information.

Contact Support

F-Secure customers can request support online via the Request support or the Chat forms on our Home - Global site.

Technical Details

System installation

The backdoor's file is a PE executable about 10 kilobytes long, packed with UPX file compressor.

When the backdoor's file is started, it copies itself as '$sys$xp.exe' file to Windows System folder and then tries to create the following startup key values in the Registry:

"$sys$cmp" = "$sys$xp.exe"

The string '$sys' is used for hiding the backdoor using Sony's XCP DRM software. This is successful only if the DRM is installed after the backdoor. If the DRM is already installed, the backdoor fails to install itself on system.

The backdoor creates mutex '$sys$xp.exe' for making sure only one copy of the backdoor runs at the same time. It might also create a mutex named 'Super'.

Bot functionality

When the backdoor is active, it connects to an IRC server, joins a certain channel and acts as a bot there.

The following IRC servers and ports are used by the backdoor:

The backdoor joins the following password-protected IRC channel:


A hacker can send commands to the bots to control infected computers. Several tasks can be performed, including the following:

- Download and execute files from remote servers
- Request system information
- Delete files

F-Secure Anti-Virus detects this malware with the following update:

Detection Type: PC

Database: 2005-11-10_04

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