W32/Rbot-VN

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.

W32/Rbot-VN is a worm with backdoor Trojan functionality.

W32/Rbot-VN is capable of spreading to computers on the local network protected by weak passwords after receiving the appropriate backdoor command.

W32/Rbot-VN will attempt to spread by exploiting the following vulnerabilities:

DCOM (MS04-012)
LSASS (MS04-011)

When first run, W32/Rbot-VN copies itself to the Windows system folder as RANT.EXE and runs this copy of the worm. The copy will then attempt to delete the original file. In order to run each time a user logs in, W32/Rbot-VN will set the following registry entries:

HKCU\Software\Microsoft\Windows\CurrentVersion\Run
rant
rant.exe

HKLM\Software\Microsoft\Windows\CurrentVersion\Run
rant
rant.exe

HKLM\Software\Microsoft\Windows\CurrentVersion\RunServices
rant
rant.exe

The worm runs continuously in the background providing backdoor access to the infected computer over IRC channels.

W32/Rbot-VN will alter the following registry entries in order to disable DCOM and close restrictions on IPC$ shares:

HKLM\SOFTWARE\Microsoft\Ole
EnableDCOM
N

HKLM\SYSTEM\CurrentControlSet\Control\Lsa
restrictanonymous
1

W32/Rbot-VN is capable of altering the following registry entry to restrict anonymous enumeration of SAM accounts:

HKLM\SYSTEM\CurrentControlSet\Control\Lsa\restrictanonymousSAM

W32/Rbot-VN can add and delete network shares and users on the infected computer. The worm can also change the network logon rights of accounts in the local system policy.