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Malware type: Worm

Aliases: Backdoor.Win32.Rbot.bh (Kaspersky), W32/Sdbot.worm.gen (McAfee), W32.Spybot.Worm (Symantec), Worm/Rbot.KR (Avira), W32/Rbot-HP (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 memory-resident worm takes advantage of the following Windows vulnerabilities to propagate across networks:

  • Remote Procedure Call (RPC) Distributed Component Object Model (DCOM) vulnerability
  • IIS5/WEBDAV Bbuffer Overrun vulnerability
  • LSASS vulnerability

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

It uses a list of user names and passwords to force its way into target machines and drops a copy of itself as SYSENTRY.EXE or SYSENTRY32.EXE in the Windows system folder.

This worm also has backdoor capabilities. It has a built-in Internet Relay Chat (IRC) client engine that connects to a specific IRC server. It then joins a particular channel, where it receives several malicious commands. It also steals CD keys of certain online game applications.

It is compressed using EXEStealth and runs on Windows 95, 98, ME, NT, 2000, and XP.

For additional information about this threat, see:

Description created: Sep. 6, 2004 9:13:28 AM GMT -0800
Description updated: Sep. 8, 2004 1:04:11 PM GMT -0800

Minimum scan engine version needed: 6.810

Pattern file needed: 2.171.14

Pattern release date: Sep 6, 2004

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 Engine and Template.


Terminating the Malware Program

This procedure terminates the running malware process.

  1. Open Windows Task Manager.
    On Windows 95, 98, and ME, press
    On Windows NT, 2000, and XP, press
    CTRL+SHIFT+ESC, then click the Processes tab.
  2. In the list of running programs*, locate any of the following processes:
  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.

*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:
    System Uptime Server = "<dropped_file>"
  4. In the left panel, double-click the following:
  5. In the right panel, locate and delete the entry:
    System Uptime Server = "<dropped_file>"
  6. In the left panel, double-click the following:
  7. In the right panel, locate and delete the entry:
    System Uptime Server = "<dropped_file>"
  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.

Users running other Windows versions can proceed with the succeeding procedure sets.

Running Trend Micro Antivirus

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

Applying Patches

This malware exploits known vulnerabilities in Windows. Download and install the fix patch supplied by Microsoft in the following pages:

Refrain from using this product until the appropriate patch has been installed. Trend Micro advises users to download critical patches upon release by vendors.

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