BKDR_FAKEMS.ZZXX
Trojan:Win32/Comisproc (Microsoft), a variant of Win32/Agent.TDQ (ESET), Trojan-Dropper.Win32.Agent.gonr (Kaspersky), Dropped:Trojan.Generic.6827920 (FSecure)
Windows 2000, Windows XP, Windows Server 2003
![](/vinfo/imgFiles/legend.jpg)
Threat Type: Backdoor
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
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.
TECHNICAL DETAILS
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.)
SOLUTION
Step 1
Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.
Step 2
Restart in Safe Mode
Step 3
Delete this registry value
Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SvcHost
- netgroup = "TPAutoConSvc"
- netgroup = "TPAutoConSvc"
Step 4
Delete this registry key
Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry. Before you could do this, you must restart in Safe Mode. For instructions on how to do this, you may refer to this page If the preceding step requires you to restart in safe mode, you may proceed to edit the system registry.
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
- TPAutoConSvc
- TPAutoConSvc
Step 5
Search and delete this file
- %System%\tpautosvc.dll
Step 6
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_FAKEMS.ZZXX. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.
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