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Aliases :

Mocbot.A, Backdoor.Win32.Mocbot.a, IRCBot.ST


Mocbot is an IRC bot that can spread using a vulnerability in Windows Plug and Play service (MS05-039).

Note: IRCBot.ST is also known as Mocbot. If you are directed to this description as of August 13, 2006, please also see the description for IRCBot.ST.


Based on the settings of your F-Secure security product, it will either move the file to the quarantine where it cannot spread or cause harm, or remove it.

A False Positive is when a file is incorrectly detected as harmful, usually because its code or behavior resembles known harmful programs. A False Positive will usually be fixed in a subsequent database update without any action needed on your part. If you wish, you may also:

  • Check for the latest database updates

    First check if your F-Secure security program is using the latest updates, then try scanning the file again.

  • Submit a sample

    After checking, if you still believe the file is incorrectly detected, you can submit a sample of it for re-analysis.

    Note: If the file was moved to quarantine, you need to collect the file from quarantine before you can submit it.

  • Exclude a file from further scanning

    If you are certain that the file is safe and want to continue using it, you can exclude it from further scanning by the F-Secure security product.

    Note: You need administrative rights to change the settings.

Technical Details

Installation to the System

The bot's file is a PE executable, 7846 bytes long, packed with MEW file compressor. When the bot's file is started, it copies itself as 'wudpcom.exe' file to Windows System folder and then creates a service with following attributes:

  • Service path: wudpcom.exe
  • Service name: Windows UDP CommunicationService short name: wudpcom
  • Description: Provides communication between clients and servers over UDP. If this service is stopped, UDP communication between clients and servers on the network will be impaired. If this service is disabled, any services that explicitly depend on it will fail to start.

Bot Functionality

When the bot is active, it connects to an IRC server, joins a particular channel, and acts as a bot there. The following IRC servers are used by the bot:


The bot joins to a password-protected IRC channel where the hacker can send commands to the bots in order to control infected computers. Several tasks can be performed, including the following:

  • Perform SYN and UDP flood
  • Download and execute files
  • Start command shell
  • Scan and exploit computers vulnerable to MS05-039

Spreading via MS05-039

The bot scans for random IP addresses and exploits a vulnerability in the Windows Plug and Play Service (MS05-039). Info on this PnP vulnerability is available here:

The vulnerability can be exploited via 139/TCP and 445/TCP.