Malware type: Worm

Aliases: Backdoor.Win32.SdBot.awk (Kaspersky), W32/Sdbot.worm.gen.h (McAfee), Trojan.Packed.NsAnti (Symantec), TR/Crypt.PCMM.Gen (Avira), Mal/Packer (Sophos),

In the wild: Yes

Destructive: No

Language: English

Platform: Windows NT, 2000, XP

Encrypted: No

Overall risk rating:

Reported infections:

Damage potential:


Distribution potential:



This worm takes advantage of the following Windows vulnerabilities:

  • Remote Procedure Call (RPC) Distributed Component Object Model (DCOM) vulnerability
  • Windows LSASS vulnerability

For more information about these Windows vulnerabilities, please refer to the following Microsoft Web pages:

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

This worm has backdoor capabilities. It executes commands sent in via Internet Relay Chat (IRC) and can be used to launch a Denial of Service (DoS) attack against specified target sites.

It steals the CD keys of popular game applications.

For additional information about this threat, see:

Description created: Feb. 27, 2005 10:44:36 AM GMT -0800
Description updated: Feb. 27, 2005 11:06:07 AM GMT -0800


File type: PE

Memory resident:  Yes

Size of malware: 150,142 Bytes (compressed);
1,720,320 Bytes (uncompressed)

Ports used: Varies

Initial samples received on: Feb 27, 2005

Vulnerability used:  (MS04-011) Security Update for Microsoft Windows (835732), (MS03-026) Buffer Overrun In RPC Interface Could Allow Code Execution

Payload 1: Compromises system security

Trigger condition 1: Upon execution

Payload 2: Performs DoS attacks

Trigger condition 1: Upon execution

Payload 3: Steals CD keys

Trigger condition 1: Upon execution


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

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

Start Upping = "mcrt32.exe"

Start Upping = "mcrt32.exe"

Start Upping = "mcrt32.exe"

It also creates the following registry entry as part of its installation routine:

Start Upping = "mcrt32.exe"

Network Propagation and Exploits

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 also exploits the Windows LSASS vulnerability, which is a buffer overrun that allows remote code execution and enables an attacker to gain full control of affected systems. This vulnerability is discussed in detail in the following pages:

It also generates IP addresses and attempts to drop a copy of the worm into the following default shares:

  • $chan
  • $chr(
  • $rndnick
  • $server
  • $user
  • ADMIN$
  • 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:

  • Add/remove default network shares
  • Change IRC server and channel where malware connects to
  • Delete files
  • Download and execute files
  • Emulate an FTP server
  • Enable DCOM protocol
  • Flush DNS cache
  • Get system information such as: CPU speed, free memory, uptime, free disk space
  • List and terminate services and processes
  • Log keystrokes
  • Redirect connections
  • Scan local area network for listening ports

Information Theft

This worm steals AOL Instant Messenger user names, Microsoft Windows product IDs, and the CD keys of the following popular games:

  • Battlefield 1942
  • Battlefield 1942 (Road To Rome)
  • Battlefield 1942 (Secret Weapons of WWII)
  • Battlefield Vietnam
  • Black and White
  • Call of Duty
  • Chrome
  • Command and Conquer: Generals
  • Command and Conquer: Generals (Zero Hour)
  • Command and Conquer: Red Alert
  • Command and Conquer: Red Alert 2
  • Command and Conquer: Tiberian Sun
  • FIFA 2002
  • FIFA 2003
  • Freedom Force
  • Global Operations
  • Ground Control II
  • Gunman Chronicles
  • Half-Life
  • Hidden & Dangerous 2
  • Industry Giant 2
  • James Bond 007: Nightfire
  • Joint Operations
  • Legends of Might and Magic
  • Medal of Honor: Allied Assault
  • Medal of Honor: Allied Assault: Breakthrough
  • Medal of Honor: Allied Assault: Spearhead
  • NHL 2002
  • NHL 2003
  • Nascar Racing 2002
  • Nascar Racing 2003
  • Need For Speed Hot Pursuit 2
  • Need For Speed: Underground
  • Neverwinter Nights
  • Neverwinter Nights (Hordes of the Underdark)
  • Neverwinter Nights (Shadows of Undrentide)
  • Rainbow Six III RavenShield
  • Shogun: Total War: Warlord Edition
  • Soldier of Fortune II - Double Helix
  • Soldiers Of Anarchy
  • The Gladiators
  • Unreal Tournament 2003
  • Unreal Tournament 2004

Denial of Service Attack

This worm allows remote users to launch the following types of flood attacks from infected machines against a target site:

  • DDoS flood
  • ICMP flood
  • PING flood
  • SYN flood
  • TCP flood
  • UDP flood

Analysis By: Michelle Perona


Minimum scan engine version needed: 6.810

Pattern file needed: 3.845.00

Pattern release date: Oct 13, 2006

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.


Identifying the Malware Program

To remove this malware, first identify the malware program.

  1. Scan your system with your Trend Micro antivirus product.
  2. NOTE all files detected as WORM_SDBOT.ASN.

Trend Micro customers need to download the latest pattern file before scanning their system. Other users can use Housecall, Trend Micro�s online virus scanner.

Terminating the Malware Program

This procedure terminates the running malware process. You will need the name(s) of the file(s) detected earlier.

  1. Open Windows Task Manager.
    � On Windows NT, 2000, and XP, press
    CTRL%20SHIFT%20ESC, then click the Processes tab.
  2. In the list of running programs*, locate the malware file(s) detected earlier.
  3. Select one of the detected files, then press either the End Task or the End Process button, depending on the version of Windows on your system.
  4. Do the same for all detected malware files in the list of running processes.
  5. To check if the malware process has been terminated, close Task Manager, and then open it again.
  6. 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:
    Start Upping = "mcrt32.exe"
  4. In the left panel, double-click the following:
  5. In the right panel, locate and delete the entry:
    Start Upping = "mcrt32.exe"
  6. In the left panel, double-click the following:
  7. In the right panel, locate and delete the entry:
    Start Upping = "mcrt32.exe"

Removing Other Malware Entries from the Registry

  1. In the left panel, double-click the following:
  2. In the right panel, locate and delete the entry:
    Start Upping = "mcrt32.exe"
  3. 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.

Running Trend Micro Antivirus

Scan your system with Trend Micro antivirus and delete all files detected as WORM_SDBOT.ASN. 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 Patches

Download the latest patches. Information on the vulnerabilities exploited by this malware and corresponding patches can be found at the following links:

Microsoft Security Bulletin MS03-026
Microsoft Security Bulletin MS04-011

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