WORM_RBOT.EIW

Malware type: Worm

Aliases: Backdoor.Win32.Rbot.aeu (Kaspersky), W32/Sdbot.worm.gen.as (McAfee), W32.Spybot.Worm (Symantec), Worm/Rbot.210944 (Avira), W32/Rbot-ELA (Sophos), Backdoor:Win32/Rbot (Microsoft)

In the wild: Yes

Destructive: No

Language: English

Platform: Windows 98, ME, NT, 2000, XP, Server 2003

Encrypted: No

Overall risk rating:

Reported infections:

Damage potential:

High

Distribution potential:

High

Infection Channel 1 : Propagates via network shares


Infection Channel 2 : Propagates via software vulnerabilities


Description: 

This worm spreads by dropping a copy of itself into network shared folders. It gains access to these shares by using a list of user names and passwords. It also exploits the RPC Interface Buffer Overrun vulnerability. More information about the said vulnerability can be found in this page:

This worm has backdoor capabilities. It opens various ports, connects to an Internet Relay Chat (IRC) server, and joins several channels upon connection. It listens for commands coming from a remote user, which it executes on the affected computer.

For additional information about this threat, see:

Description created: Apr. 13, 2006 3:51:49 AM GMT -0800


TECHNICAL DETAILS


File type: PE

Memory resident:  Yes

Size of malware: 83,456 Bytes (compressed)

Ports used: Varies

Initial samples received on: Apr 7, 2006

Compression type: Neolite

Vulnerability used:  (MS03-026) Buffer Overrun In RPC Interface Could Allow Code Execution

Payload 1: Compromises system security

Details:

Installation and Autostart Technique

Upon execution, this worm drops a copy of itself as JSSSVC.EXE in the Windows system folder. It then creates the following registry entries to ensure its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
jssvc23 = "jsssvc.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\RunServices
jssvc23 = "jsssvc.exe"

It also modifies the following entries as part of its installation routine:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Ole
EnableDCOM = "N"

The default value of EnableDCOM is "Y".

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\Lsa
Restrictanonymous = "dword:00000001"

There is no default value for RestrictAnonymous, it is modified from the value set by the user.

Propagation via Network Shares and Software Vulnerabilities

This worm spreads by dropping a copy of itself into network shared folders. It gains access to these shares by using a list of user names and passwords. It also exploits the RPC Interface Buffer Overrun vulnerability. More information about the said vulnerability can be found in this page:

Backdoor Capabilities and Other Details

This worm has backdoor capabilities. It opens various ports, connects to the Internet Relay Chat (IRC) server sigs.stropereht.biz, and joins the channels ##j2 and ##jdownload2 upon connection. It listens for the following commands coming from a remote user, which it executes on the affected computer:

  • Launch a denial of service attack against target IP addresses
  • Run programs
  • Scan for vulnerable systems
  • Steal CD keys of popular games installed in the affected computer

This worm runs on Windows 98, ME, NT, 2000, XP, and Server 2003.

Analysis By: Donne Celadi�a

Updated By: Mary Grace C. Gabriel

Revision History:

First pattern file version: 3.320.02
First pattern file release date: Apr 08, 2006
 
Apr 16, 2006 - Modified Virus Report

SOLUTION


Minimum scan engine version needed: 7.500

Pattern file needed: 3.504.01

Pattern release date: Jun 14, 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.

Solution:

Terminating the Malware Program

This procedure terminates the running malware process.

  1. Open Windows Task Manager.
    • On Windows 98 and ME, press
    CTRL%20ALT%20DELETE
    • On Windows NT, 2000, XP, and Server 2003, press
    CTRL%20SHIFT%20ESC, then click the Processes tab.
  2. In the list of running programs*, locate the process:
    jsssvc.exe
  3. Select the malware process, then press either the End Task or the End Process button, depending on the version of Windows on your computer.
  4. To check if the malware process has been terminated, close Task Manager, and then open it again.
  5. Close Task Manager.

*NOTE: On computers running Windows 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.

On computers running all Windows platforms, if the process you are looking for is not in the list displayed by Task Manager or Process Explorer, continue with the next solution procedure, noting additional instructions. If the malware process is in the list displayed by either Task Manager or Process Explorer, but you are unable to terminate it, restart your computer in safe mode.

Editing the Registry

This malware modifies the computer's registry. Users affected by this malware may need to modify or delete specific registry keys or entries. For detailed information regarding registry editing, please refer to the following articles from Microsoft:

  1. HOW TO: Backup, Edit, and Restore the Registry in Windows 95, Windows 98, and Windows ME
  2. HOW TO: Backup, Edit, and Restore the Registry in Windows NT 4.0
  3. HOW TO: Backup, Edit, and Restore the Registry in Windows 2000
  4. HOW TO: Back Up, Edit, and Restore the Registry in Windows XP and Server 2003

Removing Autostart Entries from the Registry

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

If the registry entries below are not found, the malware may not have executed as of detection. If so, proceed to the succeeding solution set.

  1. Open Registry Editor. Click Start>Run, type REGEDIT, then press Enter.
  2. In the left panel, double-click the following:
    HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft>
    Windows>CurrentVersion>Run
  3. In the right panel, locate and delete the entry:
    jssvc23 = "jsssvc.exe"
  4. In the left panel, double-click the following:
    HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft>
    Windows>CurrentVersion>RunServices
  5. In the right panel, locate and delete the entry:
    jssvc23 = "jsssvc.exe"

Restoring EnableDCOM and RestrictAnonymous Registry Entries

This malware modifies EnableDCOM and RestrictAnonymous registry entries to a certain value. To know more about restoring these registries to their original values, please refer to these articles:

  1. COM security frequently asked questions
  2. How to disable DCOM support in Windows
  3. How to Use the RestrictAnonymous Registry Value in Windows 2000
  4. The "RestrictAnonymous" Registry Value May Break the Trust to a Windows 2000 Domain

To restore this entry to its default value, please perform the following instructions:

  1. Still in Registry Editor, in the left panel, double-click the following:
    HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft>Ole
  2. In the right panel, locate the entry:
    EnableDCOM = "N"
  3. Right-click on this registry entry and choose Modify. Change the value of this entry to:
    EnableDCOM = "Y"
  4. Close Registry Editor.

Important Windows ME/XP Cleaning Instructions

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

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

Running Trend Micro Antivirus

If you are currently running in safe mode, please restart your computer normally before performing the following solution.

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

Applying Patch

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




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