BKDR_FAKEMS.ZZXX

This backdoor arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It executes commands from a remote malicious user, effectively compromising the affected system. However, as of this writing, the said sites are inaccessible.

Arrival Details

This backdoor arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Autostart Technique

This backdoor registers its dropped component as a system service to ensure its automatic execution at every system startup. It does this by creating the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\TPAutoConSvc

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\TPAutoConSvc

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\TPAutoConSvc

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\TPAutoConSvc
Type = "0x00000020"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\TPAutoConSvc
Start = "0x00000002"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\TPAutoConSvc
ImagePath = "%systemroot%\system32\svchost.exe -k netgroup"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\TPAutoConSvc
ErrorControl = "0x00000001"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\TPAutoConSvc
DisplayName = "TP AutoConnection Service"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\TPAutoConSvc
Group = "netsvcs"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\TPAutoConSvc\Parameters
ServiceDll = "%systemroot%\system32\tpautosvc.dll"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\TPAutoConSvc\Security
Security = {hex values}

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\TPAutoConSvc\Enum
0 = "Root\LEGACY_TPAUTOCONSVC\0000"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\TPAutoConSvc\Enum
Count = "0x00000001"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\TPAutoConSvc\Enum
NextInstance = "0x00000001"

It registers its dropped component as a system service to ensure its automatic execution at every system startup. It does this by creating the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\TPAutoConSvc

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\TPAutoConSvc\Parameters

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\TPAutoConSvc\Security

Other System Modifications

This backdoor adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\SvcHost
netgroup = "TPAutoConSvc"

Backdoor Routine

This backdoor executes the following commands from a remote malicious user:

• Perform Remote Shell

It connects to the following URL(s) to send and receive commands from a remote malicious user:

• gmail.{BLOCKED}ktw.com - using port 80 and 443

However, as of this writing, the said sites are inaccessible.

Dropping Routine

This backdoor drops the following files:

• %System%\tpautosvc.dll

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)