Sophos

W32/Rbot-HE

Aliases
  • Backdoor.Rbot.gen
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 25 August 2004 20:24:44 (GMT)
Detected by All Sophos products
  • Endpoint Security and Control 9.0
  • Small business solutions 4.0

Action

Please follow the instructions for removing worms.

You will also need to edit the following registry entries, if 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\
Microsoft Update Machine
HKLM\Software\Microsoft\Windows\CurrentVersion\RunServices\
Microsoft Update Machine

and delete them if they exist.

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

HKCU\[code number]\Software\Microsoft\Windows\CurrentVersion\Run\
Microsoft Update Machine

and delete it if it exists.

Close the registry editor.

  • Check your administrator passwords and review network security.
  • 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.

More Information

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

W32/Rbot-HE 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-HE copies itself to the Windows system folder as WUAMGRD.EXE and creates entries at the following locations in the registry so as to run itself on system startup:

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

W32/Rbot-HE may set the following registry entries:

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

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

W32/Rbot-HE may attempt to log the user's keystrokes to a file SYSTEM.TXT in the Windows system folder.

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