Home > Threat descriptions >



Category: Malware

Type: Backdoor

Aliases: Backdoor:W32/SdBot


Backdoor:W32/SdBot comprises a large family of remote access utilities known to be used by hackers to gain unauthorized control of a user's computer system.


Automatic action

Once detected, the F-Secure security product will automatically handle a harmful program or file by either deleting or renaming it.

Eliminating a Local Network Outbreak

If the infection is in a local network, please follow the instructions on this webpage:

Manual Disinfection

Caution: Manual disinfection is a risky process; it is recommended only for advanced users.

Manual disinfection for SDBot backdoor requires renaming of an infected file, usually located in Windows or Windows System folder and restarting a system. Please note that the backdoor's file may have read-only, system and hidden attributes, so Windows Explorer has to be configured to show such files.

Knowledge Base

Find the latest advice in our Community Knowledge Base.

About the product

See the manual for your F-Secure product on the Help Center.

Contact Support

Chat with or call an expert for help.

Submit a sample

Submit a file or URL for further analysis.

Technical Details

Variants in the SdBot family include:


Based on the variant, SdBot backdoors copy themselves either to the Windows System directory, or to other directories located in the System directory. It also ensures the copy is started when the system stars by creating a subkey in one of the following registry keys:

  • HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunServices
  • HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run

The name of subkey and its value differ depending on the variant.


SdBot backdoors connect to various IRC servers, joining an IRC channel (the choice of channel is hardcoded into the code) in order to receive instruction from the attacker(s). The backdoor can perform a variety of actions, including acting as an IRC proxy server, downloading and executing remote files, sending messages and more.