Sophos

W32/Rbot-NC

Aliases
  • Backdoor.Win32.Rbot.gen
  • W32/Sdbot.worm.gen.j
Category
Type
What to do
Prevalence low high

Summary

 
How it spreads
  • Network shares
Affected operating systems Windows
Characteristics
  • Installs itself in the registry
Protection available since 16 October 2004 15:51:01 (GMT)
Detected by All Sophos products
  • Free virus, spyware, and adware scan
  • Test your existing anti-virus protection
  • Find threats your anti-virus missed

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.

More Information

W32/Rbot-NC is a network worm which contains IRC backdoor Trojan functionality, allowing unauthorised remote access to the infected computer. W32/Rbot-NC 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-NC 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 attacker.

W32/Rbot-NC copies itself to the Windows system folder as SCHOST.EXE and creates entries at the following locations in the registry with the value Generic Host Process to run itself on system startup:

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

W32/Rbot-NC may attempt to set the following registry entries:

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

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

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