BKDR_PLUGX.NT
Backdoor:Win32/Plugx.A (Microsoft), Trojan.Win32.Generic.pak!cobra (Sunbelt), Backdoor.Win32.Plugx, Backdoor.Win32.Plugx (Ikarus)
Windows 2000, Windows XP, Windows Server 2003
Threat Type: Backdoor
Destructiveness: No
Encrypted: Yes
In the wild: Yes
OVERVIEW
This backdoor arrives as an attachment to email messages spammed by other malware/grayware or malicious users.
TECHNICAL DETAILS
295,736 bytes
EXE
Yes
20 Jul 2012
Arrival Details
This backdoor arrives as an attachment to email messages spammed by other malware/grayware or malicious users.
Installation
This backdoor drops the following files:
- %System Root%\Documents and Settings\All Users\SxS\bug.log
- %System Root%\Documents and Settings\All Users\SxSq\rc.exe
- %System Root%\Documents and Settings\All Users\SxSq\rc.hlp
- %System Root%\Documents and Settings\All Users\SxSq\rcdll.dll
- %User Temp%\1.exe
- %User Temp%\2.doc
(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.. %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)
It creates the following folders:
- %System Root%\Documents and Settings\All Users\SxS
- %System Root%\Documents and Settings\All Users\SxSq
(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)
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\SxSq
Description = "SxSq"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SxSq
DisplayName = "SxSq"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SxSq
ErrorControl = "0"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SxSq
ImagePath = ""%System Root%\Documents and Settings\All Users\SxSq\rc.exe" 200 0"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SxSq
ObjectName = "LocalSystem"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SxSq
Start = "2"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SxSq
Type = "110"
Other System Modifications
This backdoor adds the following registry keys:
HKEY_CLASSES_ROOT\FAST
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SxSq
Other Details
This backdoor connects to the following possibly malicious URL:
- {BLOCKED}.{BLOCKED}.231.6:443
SOLUTION
9.200
9.274.03
20 Jul 2012
9.275.00
21 Jul 2012
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 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_CLASSES_ROOT
- FAST
- FAST
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
- SxSq
- SxSq
Step 4
Search and delete these folders
- %System Root%\Documents and Settings\All Users\SxS
- %System Root%\Documents and Settings\All Users\SxSq
Step 5
Search and delete these files
- %User Temp%\1.exe
- %User Temp%\2.doc
Step 6
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_PLUGX.NT. 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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