W32/Rbot-AIH

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.

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-AIH is a worm and IRC backdoor Trojan for the Windows platform.

W32/Rbot-AIH spreads:

- to other network computers by exploiting common buffer overflow vulnerabilites, including:

LSASS (MS04-011),
RPC-DCOM (MS04-012),
WebDav (MS03-007),
IIS5SSL (MS04-011) (CAN-2003-0719),
MSSQL (MS02-039) (CAN-2002-0649),
UPNP (MS01-059) and
Dameware (CAN-2003-1030)

- by copying itself to network shares protected by weak passwords

W32/Rbot-AIH runs continuously in the background, providing a backdoor server which allows a remote intruder to gain access and control over the computer via IRC channels.

W32/Rbot-AIH includes functionality to:

- steal confidential information
- carry out DDoS flooder attacks
- silently download, install and run new software
- change security settings

When first run W32/Rbot-AIH copies itself to <System>\hostserv.exe.

The following registry entries are created to run hostserv.exe on startup:

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

HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
hostserv
hostserv.exe

HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\RunServices
hostserv
hostserv.exe

Registry entries are set as follows:

HKLM\SOFTWARE\Microsoft\Ole
EnableDCOM
N

HKLM\SYSTEM\CurrentControlSet\Control\Lsa
restrictanonymous
1

The following patches for the operating system vulnerabilities exploited by W32/Rbot-AIH can be obtained from the Microsoft website:

MS04-011
MS04-012
MS03-007
MS02-039
MS01-059