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BKDR_PLUGX.CSZ

April 24, 2013
 Analysis by: Rika Joi Gregorio
 PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:

  • 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.

  TECHNICAL DETAILS

File Size:

446,464 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

16 Apr 2013

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.

Installation

This backdoor drops the following files:

  • %All Users Profile%\SxS\bug.log

(Note: %All Users Profile% is the All Users or Common profile folder, which is C:\Documents and Settings\All Users in Windows 2000, XP, and Server 2003, and C:\ProgramData in Windows Vista and 7.)

It creates the following folders:

  • %All Users Profile%\SxS

(Note: %All Users Profile% is the All Users or Common profile folder, which is C:\Documents and Settings\All Users in Windows 2000, XP, and Server 2003, and C:\ProgramData in Windows Vista and 7.)

Other System Modifications

This backdoor adds the following registry keys:

HKEY_CLASSES_ROOT\MJ

HKEY_CURRENT_USER\Software\Local AppWizard-Generated Applications

HKEY_CURRENT_USER\Software\Local AppWizard-Generated Applications\
FastMofa

HKEY_CURRENT_USER\Software\Local AppWizard-Generated Applications\
FastMofa\Recent File List

HKEY_CURRENT_USER\Software\Local AppWizard-Generated Applications\
FastMofa\Settings

Other Details

This backdoor connects to the following possibly malicious URL:

  • http://{BLOCKED}.{BLOCKED}os.com/update?id=00159798
  • http://{BLOCKED}n.{BLOCKED}ti.com:53/update?id=00159798
  • http://{BLOCKED}.{BLOCKED}os.com:8080/update?id=00159798
  • http://{BLOCKED}.{BLOCKED}os.com/update?id=00159798

  SOLUTION

Minimum Scan Engine:

9.300

FIRST VSAPI PATTERN FILE:

9.874.03

FIRST VSAPI PATTERN DATE:

23 Apr 2013

VSAPI OPR PATTERN File:

9.875.00

VSAPI OPR PATTERN Date:

24 Apr 2013

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

[ Learn More ]

Step 3

Delete this registry key

[ Learn More ]

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
    • MJ
  • In HKEY_CURRENT_USER\Software
    • Local AppWizard-Generated Applications

Step 4

Search and delete these folders

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %All Users Profile%\SxS

Step 5

Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_PLUGX.CSZ. 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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