W32/Rbot-YP

Please follow the instructions for removing worms.

Change any data that may have become compromised.

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.

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-YP is an IRC backdoor Trojan and network worm.

W32/Rbot-YP may spread to remote network shares protected by weak passwords and computers vulnerable to common exploits. The worm also opens up a backdoor, allowing unauthorised remote access to infected computers via the IRC network, while running in the background as a service process.

The worm exploits the following vulnerabilities: RPC-DCOM (MS04-12) and LSASS (MS04-11). For patches for these vulnerabilities, see:

http://www.microsoft.com/technet/security/bulletin/ms04-011.mspx
http://www.microsoft.com/technet/security/bulletin/ms04-012.mspx

W32/Rbot-YP can receive commands from a remote intruder to delete network shares, log keypresses, participate in DDoS attacks, scan other computers for vulnerabilities, steal passwords, steal registration keys for computer games, create administrator accounts, terminate firewall and anti-virus processes and capture video from webcameras attached to the computer.

The worm ensures that it is run each time a user logs on by adding the following registry entries:

HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
ApPache System
"ApPache.exe"

HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\RunServices
ApPache System
"ApPache.exe"

W32/Rbot-YP also creates this registry entry:

HKCU\Software\Microsoft\OLE
ApPache System
"ApPache.exe"

The worm hardens the computer against further attack by setting the following registry entries, if they were not already set:

HKLM\SOFTWARE\Microsoft\Ole
EnableDCOM
"N"

HKLM\SYSTEM\CurrentControlSet\Control\Lsa
restrictanonymous
1