Sophos

W32/Rbot-LT

Aliases
  • Backdoor.Win32.Rbot.cd
Category
Type
What to do
Prevalence low high

Summary

 
How it spreads
  • Network shares
Affected operating systems Windows
Characteristics
  • Installs itself in the registry
Included in our products from June 2006 (4.06)
Protection available since 6 October 2004 08:52:21 (GMT)
Last updated 20 April 2006 09:01:26 (GMT)
Detected by All Sophos products

Action

Please follow the instructions for removing worms.

You will also need to edit the following registry entries, if they are present. Please read the warning about editing the registry.

At the taskbar, click Start|Run. Type 'Regedit' and press Return. The registry editor opens.

Before you edit the registry, you should make a backup. On the 'Registry' menu, click 'Export Registry File'. In the 'Export range' panel, click 'All', then save your registry as Backup.

Locate the HKEY_LOCAL_MACHINE entries:

HKLM\Software\Microsoft\Windows\CurrentVersion\Run

HKLM\Software\Microsoft\Windows\CurrentVersion\RunServices

and remove any reference to any file you deleted.

Each user has a registry area named HKEY_USERS\[code number indicating user]\. For each user locate the entry:

HKU\[code number]\Software\Microsoft\Windows\
CurrentVersion\Run\

and remove any reference to any file you deleted.

Close the registry editor.

Check the following items

  • To renable DCOM you can edit the registry, but it's better to use Dcomcnfg.exe. See Microsoft article 825750 for details.
  • The HKLM\SYSTEM\CurrentControlSet\Control\Lsa\restrictanonymous = "1" setting does not allow enumeration of SAM accounts and names. The default is "0". It can be changed in Local Security Policy. See Microsoft article 246261 for details.
  • Check your administrator passwords and review network security.
  • Delete the file KEY32.TXT in the Windows system folder, if it is present.

More Information

W32/Rbot-LT is a network worm which contains IRC backdoor Trojan functionality, allowing unauthorised remote access to the infected computer. W32/Rbot-LT is a worm which attempts to spread to remote network shares. It also contains backdoor Trojan functionality, allowing unauthorised remote access to the infected computer via IRC channels while running in the background as a service process.

W32/Rbot-LT spreads to network shares with weak passwords and via network security exploits as a result of the backdoor Trojan element receiving the appropriate command from a remote user.

W32/Rbot-LT copies itself to the Windows system folder as LSSRV.EXE and creates entries at the following locations in the registry with the value Microsoft Services so as to run itself on system startup, resetting them multiple times every minute:

HKLM\Software\Microsoft\Windows\CurrentVersion\Run
HKLM\Software\Microsoft\Windows\CurrentVersion\RunServices

W32/Rbot-LT also sets the following registry entry with the same value to point to itself:

HKCU\Software\Microsoft\OLE

W32/Rbot-LT may attempt to sets the following registry entries:

HKLM\SOFTWARE\Microsoft\Ole\EnableDCOM = "N"
HKLM\SYSTEM\CurrentControlSet\Control\Lsa\restrictanonymous = "1"

W32/Rbot-LT may attempt to delete network shares on the host computer.

W32/Rbot-LT may attempt to log keystrokes to the file KEY32.TXT in the Windows system folder.

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