Malware type: Worm

Aliases: Backdoor.Win32.IRCBot.bl (Kaspersky), W32/Sdbot.worm.gen (McAfee), Backdoor.Sdbot (Symantec), Worm/SdBot.37888.10 (Avira), W32/Sdbot-TD (Sophos),

In the wild: Yes

Destructive: Yes

Language: English

Platform: Windows NT, 2000, XP

Encrypted: Yes

Overall risk rating:

Reported infections:

Damage potential:


Distribution potential:



This memory-resident worm propagates across networks by dropping a copy of itself into default shared folders. It uses a list of user names and passwords to access machines.

It operates as an Internet Relay Chat (IRC) bot that connects to an IRC server. It then joins an IRC channel, where it waits for several commands from a malicious user.

For additional information about this threat, see:

Description created: Mar. 14, 2005 2:23:54 AM GMT -0800
Description updated: Mar. 14, 2005 2:23:55 AM GMT -0800


Memory resident:  Yes

Size of malware: 37,888 Bytes

Initial samples received on: Mar 12, 2005

Compression type: Morphine

Payload 1: Compromises system security

Trigger condition 1: Upon execution

Payload 2: Terminates processes

Trigger condition 1: Upon execution


Installation and Autostart Techniques

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

To enable its automatic execution at every system startup, it creates the following registry entries:

Halit = "fuduj.exe"

Halit = "fuduj.exe"

Halit = "fuduj.exe"

Network Shares

This worm uses NetBEUI functions to get available lists of user names and passwords. It then lists down the available network shares. It uses the gathered user names and passwords to drop a copy of itself into accessed shared folders.

(Note: NetBEUI [short for NetBios Extended User Interface] is an enhanced version of the NetBIOS protocol. For more information about NetBEUI, click here.)

It also generates IP addresses and attempts to drop a copy of itself into the target address� default shares, such as:

  • ADMIN$\System32\
  • C$\Documents and Settings\All Users\Documents\
  • C$\shared\
  • C$\Windows\System32\
  • C$\WINNT\System32\
  • C\
  • IPC$\

It uses the default shares to determine access and drop copies of itself into the shared folders if it has full access rights. However, if these shared folders have restricted access rights, it attempts to access the machines by logging on using the following user names and passwords:

  • access
  • accounting
  • accounts
  • admin
  • administrateur
  • administrator
  • backup
  • barbara
  • blank
  • bruce
  • capitol
  • changeme
  • cisco
  • compaq
  • control
  • database
  • databasepass
  • databasepassword
  • db1234
  • dbpass
  • dbpassword
  • default
  • domain
  • domainpass
  • domainpassword
  • exchange
  • exchnge
  • freddy
  • guest
  • headoffice
  • heaven
  • homeuser
  • internet
  • intranet
  • katie
  • login
  • loginpass
  • nokia
  • oeminstall
  • oemuser
  • office
  • orange
  • pass1234
  • passwd
  • password
  • password1
  • rmove
  • siemens
  • sqlpass
  • staff
  • student
  • student1
  • teacher
  • technical
  • threads
  • turnip
  • user1
  • userpassword
  • win2000
  • win2k
  • win98
  • windows
  • winnt
  • winpass
  • winxp
  • yellow

Backdoor Capabilities

This worm also has backdoor capabilities.

It opens a random port and operates as an Internet Relay Chat (IRC) bot that connects to an IRC server. It then joins an IRC channel, where it waits for several commands from a malicious user.

It has the following capabilities:

  • Change IRC server and channel
  • Run commands
  • Get system information(such as CPU speed, RAM, and free space)
  • Get server information
  • Download and execute files
  • Add or remove default network shares
  • Delete files
  • Log keystrokes
  • List and terminate processes and services
  • Delete or add services
  • Delete or add autostart registry entries
  • Update the bot from an FTP or HTTP URL
  • Shut down or restart the machine

The following CVAR commands are used to control the IRC Cvar:

  • List Cvars
  • Display the value of a Cvar
  • Set the value of a Cvar

(Note: Cvars are IRC default variables that allows channel creators to prompt users into modifying the system settings.)

Analysis By: Earl Lim Manly


Minimum scan engine version needed: 6.810

Pattern file needed: 2.493.01

Pattern release date: Mar 14, 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.
    To do this, press
    CTRL%20SHIFT%20ESC, then click the Processes tab.
  2. In the list of running programs*, locate the process:
  3. Select the malware process, then press either the End Task or the End Process button, depending on the version of Windows on your system.
  4. To check if the malware process has been terminated, close Task Manager, and then open it again.
  5. Close Task Manager.

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:
    halit = "fuduj.exe"
  4. In the left panel, double-click the following:
  5. In the right panel, locate and delete the entry:
    halit = "fuduj.exe"
  6. In the left panel, double-click the following:
  7. In the right panel, locate and delete the entry:
    halit = "fuduj.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 XP Cleaning Instructions

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

Users running other Windows versions can proceed with the succeeding procedure set(s).

Running Trend Micro Antivirus

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

Trend Micro offers best-of-breed antivirus and content-security solutions for your corporate network, small and medium business, mobile device or home PC.