Description: 

This memory resident worm propagates via network shares. It accesses these shares by using a list of user names and passwords.

It has backdoor capabilities which enables it to open random ports and connect to a specified IRC (Internet Relay Chat) server. When a connection is establiched, it can carry out malicious commands on a remote target system.

It also has the ability to steal CD keys of popular game applications, as well as perform a denial of service (DoS) attack on a remote location.

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

Details:

Installation and Autostart Technique

Upon execution, this memory-resident worm drops a copy of itself in the Windows system folder using the following file name:

WINSME.EXE

(Note: The Windows system folder is usually C:\Windows\System on Windows 95, 98 and ME, C:\WINNT\System32 on Windows 2000 and NT, and C:\Windows\System32 on Windows XP.)

Then, it adds the entry Auto Started = "winsME.exe" to the following registry keys to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\Windows\
CurrentVersion\Runonce

HKEY_CURRENT_USER\Software\Microsoft\Windows\
CurrentVersion\Run

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\
CurrentVersion\RunOnce

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\
CurrentVersion\Run

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\
CurrentVersion\RunServices

HKEY_USERS\Win98\Software\Microsoft\Windows\
CurrentVersion\Runonce

HKEY_USERS\Win98\Software\Microsoft\Windows\
CurrentVersion\Run

Propagation via Network Shares

This malware searches for the following network shares and attempts to drop a copy of itself to these shares:

• c$\winnt\system32
• admin$\system32
• ipc$

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:

Identifying the Malware Program

Before proceeding to remove this malware, first identify the malware program.

Scan your system with Trend Micro antivirus and NOTE all files detected as WORM_RBOT.B. 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 free online virus scanner.

Restarting in Safe Mode

On Windows 95

1. Restart your computer.
2. Press F8 at the Starting Windows 95 message.
3. Choose Safe Mode from the Windows 95 Startup Menu then press Enter.

On Windows 98 and ME

1. Restart your computer.
   
2. Press the CTRL key until the startup menu appears.
   
3. Choose the Safe Mode option then press Enter.

On Windows NT (VGA mode)

1. Click Start>Settings>Control Panel.
2. Double-click the System icon.
3. Click the Startup/Shutdown tab.
4. Set the Show List field to 10 seconds and click OK to save this change.
5. Shut down and restart your computer.
6. Select VGA mode from the startup menu.

On Windows 2000

1. Restart your computer.
   
2. Press the F8 key, when you see the Starting Windows bar at the bottom of the screen.
   
3. Choose the Safe Mode option from the Windows Advanced Options Menu then press Enter.

On Windows XP

1. Restart your computer.
   
2. Press F8 after the Power-On Self Test (POST) is done. If the Windows Advanced Options Menu does not appear, try restarting and then pressing F8 several times after the POST screen.
3. Choose the Safe Mode option from the Windows Advanced Options Menu then press Enter.

Note: After performing all the solutions for the removal of this malware, please restart your system normally, and run your Trend Micro antivirus product.

Editing the Registry

This malware modifies the system'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 2003

Removing Autostart Entries from the Registry

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

To remove the malware autostart entries:

1. Open Registry Editor. To do this, click Start>Run, type Regedit, then press Enter.
2. In the left panel, double-click the following:
   HKEY_CURRENT_USER>Software>Microsoft>
   Windows>CurrentVersion>Runonce
3. In the right panel, locate and delete the entry:
   Auto Started = "winsME.exe"
4. In the left panel, double-click the following:
   HKEY_CURRENT_USER>Software>Microsoft>
   Windows>CurrentVersion>Run
5. In the right panel, locate and delete the entry:
   Auto Started = "winsME.exe"
6. In the left panel, double-click the following:
   HKEY_LOCAL_MACHINE>Software>Microsoft>
   Windows>CurrentVersion>Runonce
7. In the right panel, locate and delete the entry:
   Auto Started = "winsME.exe"
8. In the left panel, double-click the following:
   HKEY_LOCAL_MACHINE>Software>Microsoft>
   Windows>CurrentVersion>Run
9. In the right panel, locate and delete the entry:
   Auto Started = "winsME.exe"
10. In the left panel, double-click the following:
    HKEY_LOCAL_MACHINE>Software>Microsoft>
    Windows>CurrentVersion>RunServices
11. In the right panel, locate and delete the entry:
    Auto Started = "winsME.exe"
12. In the left panel, double-click the following:
    HKEY_USER>Win98>Software>Microsoft>
    Windows>CurrentVersion>Runonce
13. In the right panel, locate and delete the entry:
    Auto Started = "winsME.exe"
14. In the left panel, double-click the following:
    HKEY_USER>Win98>Software>Microsoft>
    Windows>CurrentVersion>Run
15. In the right panel, locate and delete the entry:
    Auto Started = "winsME.exe"
16. 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 systems.

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

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

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