W32/Tilebot-AM

Please follow the instructions for removing worms.

W32/Tilebot-AM is a worm and IRC backdoor Trojan for the Windows platform.

W32/Tilebot-AM spreads to other network computers by exploiting common buffer overflow vulnerabilities, including: LSASS (MS04-011), RPC-DCOM (MS04-012), PNP (MS05-039) and ASN.1 (MS04-007) and by copying itself to network shares protected by weak passwords.

W32/Tilebot-AM 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/Tilebot-AM includes functionality to:

- setup a SOCKS4 server
- access the internet and communicate with a remote server via HTTP
- harvest information from the Protected Storage areas

When first run W32/Tilebot-AM copies itself to <Windows>\_meaoi.exe and creates the file <System>\meaoi.sys.

The file meaoi.sys is detected as Troj/RKPort-Fam.

The file _meaoi,exe is registered as a new system driver service named "MEAOI", with a display name of "MEAOI Service", a description of "MEAOI Service Monitor" and a startup type of automatic, so that it is started automatically during system startup. Registry entries are created under:

HKLM\SYSTEM\CurrentControlSet\Enum\Root\LEGACY_MEAOI
HKLM\SYSTEM\CurrentControlSet\Services\MEAOI

W32/Tilebot-AM sets the following registry entries, disabling the automatic startup of other software:

HKLM\SYSTEM\CurrentControlSet\Services\Messenger
Start
4

HKLM\SYSTEM\CurrentControlSet\Services\RemoteRegistry
Start
4

HKLM\SYSTEM\CurrentControlSet\Services\TlntSvr
Start
4

Registry entries are set as follows:

HKLM\SOFTWARE\Microsoft\Security Center
AntiVirusDisableNotify
1

HKLM\SOFTWARE\Microsoft\Security Center
AntiVirusOverride
1

HKLM\SOFTWARE\Microsoft\Security Center
FirewallDisableNotify
1

HKLM\SOFTWARE\Microsoft\Security Center
FirewallOverride
1

HKLM\SOFTWARE\Microsoft\Security Center
UpdatesDisableNotify
1

HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
SFCScan
0

HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate\Auto Update
AUOptions
1

HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate\Auto Update
AUState
1

HKLM\SOFTWARE\Policies\Microsoft\WindowsFirewall\DomainProfile
EnableFirewall
0

HKLM\SOFTWARE\Policies\Microsoft\WindowsFirewall\StandardProfile
EnableFirewall
0

HKLM\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate
DoNotAllowXPSP2
1

HKLM\SOFTWARE\Microsoft\Ole
EnableDCOM
N

HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
SFCDisable
ffffff9d

HKLM\SYSTEM\CurrentControlSet\Control\Lsa
restrictanonymous
1

HKLM\SYSTEM\CurrentControlSet\Services\Messenger
Start
4

HKLM\SYSTEM\CurrentControlSet\Services\RemoteRegistry
Start
4

HKLM\SYSTEM\CurrentControlSet\Services\TlntSvr
Start
4

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

MS04-012
MS04-011
MS05-039
MS04-007