Malware type: Worm

Aliases: Trojan-Dropper.Win32.Delf.rc (Kaspersky), BackDoor-AQF (McAfee), W32.Randex (Symantec), Worm/IrcBot.231584 (Avira), Troj/Bckdr-AHR (Sophos),

In the wild: Yes

Destructive: No

Language: English

Platform: Windows 95, 98, ME, NT, 2000, XP

Encrypted: No

Overall risk rating:

Reported infections:

Damage potential:


Distribution potential:



This worm takes advantage of the Remote Procedure Call (RPC) Distributed Component Object Model (DCOM) vulnerability.

For more information about this Windows vulnerability, please refer to the following Microsoft Web page:

This worm attempts to log on to systems using a list of user names and passwords. It drops a copy of itself into accessible machines.

It has backdoor capabilities. It executes commands sent in via Internet Relay Chat (IRC).

This worm runs on Windows 95, 98, ME, NT, 2000, and XP.

For additional information about this threat, see:

Description created: Jan. 20, 2005 10:43:46 AM GMT -0800
Description updated: Jan. 20, 2005 10:58:54 AM GMT -0800


Size of malware: 37,888 Bytes (compressed)

Initial samples received on: Jan 20, 2005

Payload 1: Compromises system security

Trigger condition 1: Upon execution

Installation and Autostart Technique

Upon execution, this worm drops a copy of itself as VDDDWQ.EXE in the Windows system folder.

It then adds the following registry entries, which allow it to run automatically at every system startup:

Mfqneqfeb = "vdddwq.exe"

Mfqneqfeb = "vdddwq.exe"

Mfqneqfeb = "vdddwq.exe"

Network Propagation and Exploit

This worm takes advantage of the Remote Procedure Call (RPC) Distributed Component Object Model (DCOM) vulnerability, which allows an attacker to gain full access and execute any code on a target machine.

Read more on this vulnerability from the following page:

This worm looks for vulnerable Windows XP machines on the network by scanning for random TCP/IP addresses on port 135.

This worm copies and executes itself on vulnerable systems.

It searches for the following default network shares:

  • ADMIN$\system32
  • C$
  • C$\Documents and Settings\All Users\Documents
  • C$\shared
  • C$\Windows\system32
  • C$\WINNT\system32
  • IPC$

It uses the default shares to determine access and copies itself to the shared folders if it has full access rights. However, if these shared folders have restricted access rights, it attempts to brute-force its way into the systems by logging on using the following user names and passwords:

Backdoor Capabilities

This worm has backdoor capabilities. It connects to an Internet Relay Chat (IRC) server and automatically joins a specific channel, where it listens for commands coming from a remote user. It executes commands locally on the affected machines, providing remote users virtual control over affected systems.

It acts as a bot that responds to private messages with specific keyword triggers. The following are the corresponding actions it performs:

  • Act as an FTP server
  • Display connection type and local IP address
  • Download and execute files
  • Make a bot join and exit a channel
  • Update its copy

Analysis by: Roy Jimenez


Minimum scan engine version needed: 6.810

Pattern file needed: 2.364.01

Pattern release date: Jan 20, 2005

Important note: The "Minimum scan engine" refers to the earliest Trend Micro scan engine version guaranteed to detect this threat. However, Trend Micro strongly recommends that you update to the latest version in order to get comprehensive protection. Download the latest scan engine here.



To automatically remove this malware from your system, please use Trend Micro Damage Cleanup Template / Engine.


Terminating the Malware Program

This procedure terminates the running malware process.

  1. Open Windows Task Manager.

  2. � On Windows 95, 98, and ME, press
    � On Windows NT, 2000, and XP, press
    CTRL%20SHIFT%20ESC, then click the Processes tab.
  3. In the list of running programs*, locate the process:
  4. Select the malware process, then press either the End Task or the End Process button, depending on the version of Windows on your system.
  5. To check if the malware process has been terminated, close Task Manager, and then open it again.
  6. Close Task Manager.

*NOTE: On systems running Windows 95, 98, and ME, Windows Task Manager may not show certain processes. You can use a third party process viewer such as Process Explorer to terminate the malware process. Otherwise, continue with the next procedure, noting additional instructions.

Removing Autostart Entries from the Registry

Removing autostart entries from the registry prevents the malware from executing at startup.

  1. Open Registry Editor. Click Start>Run, type REGEDIT, then press Enter.
  2. In the left panel, double-click the following:
  3. In the right panel, locate and delete the entry:
    Mfqneqfeb = "vdddwq.exe"
  4. In the left panel, double-click the following:
  5. In the right panel, locate and delete the entry:
    Mfqneqfeb = "vdddwq.exe"
  6. In the left panel, double-click the following:
  7. In the right panel, locate and delete the entry:
    Mfqneqfeb = "vdddwq.exe"
  8. Close Registry Editor.

NOTE: If you were not able to terminate the malware process as described in the previous procedure, restart your system.

Additional Windows ME/XP Cleaning Instructions

Users running Windows ME and XP must disable System Restore to allow full scanning of infected systems.

Running Trend Micro Antivirus

Scan your system with Trend Micro antivirus and delete all files detected as WORM_RANDEX.AP. To do this, Trend Micro customers must download the latest pattern file and scan their system. Other users can use HouseCall, Trend Micro�s free online virus scanner.

Applying the Patch

Download the latest patch. Information on the vulnerability exploited by this malware and the corresponding patch can be found at the following link:

Microsoft Security Bulletin MS03-026

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