BKDR_SKSOCKET.AT
Windows 2000, XP, Server 2003
Threat Type: Backdoor
Destructiveness: No
Encrypted: No
In the wild: Yes
OVERVIEW
This backdoor is the command line tool called SkServer.
This backdoor may be dropped by other malware.
It acts as a proxy server to allow remote malicious user to use the affected systems to hide their identities when performing malicious activities.
TECHNICAL DETAILS
Arrival Details
This backdoor may be dropped by other malware.
Autostart Technique
This backdoor registers itself as a system service to ensure its automatic execution at every system startup by adding the following registry entries:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SkServer
ImagePath = {malware path and file name}.EXE
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SkServer
Start = 2
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SkServer
DisplayName = Snake SockProxy Service
Proxy Server Routine
This backdoor acts as a proxy server to allow remote malicious user to use the affected systems to hide their identities when performing malicious activities.
Other Details
Based on analysis of the codes, it has the following capabilities:
- Uses TCP port 1813 by default, but the remote malicious user can configure it to any port number.
SOLUTION
Step 1
For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.
Step 2
Identify and terminate files detected as BKDR_SKSOCKET.AT
- If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
- If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.
Step 3
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.
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
- SkServer
Step 4
Scan your computer with your Trend Micro product to delete files detected as BKDR_SKSOCKET.AT. 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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