BKDR_PLUGX.DUKNV

 Analysis by: Sammy Chua

 PLATFORM:

Windows

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

  • 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 modifies the Internet Explorer Zone Settings.

  TECHNICAL DETAILS

File Size:

2,819,072 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

03 Sep 2015

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%\BaiduData\BaiduSkin.exe
  • %All Users Profile%\BaiduData\ImeSkin.dll
  • %All Users Profile%\BaiduData\BaiduUI.dll
  • %Startup%\BaiduSkin.lnk

(Note: %All Users Profile% is the All Users folder, where it usually is C:\Documents and Settings\All Users on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\ProgramData on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

Other System Modifications

This backdoor adds the following registry keys:

HKEY_CURRENT_USER\Software\Local AppWizard-Generated Applications

HKEY_CURRENT_USER\Software\Local AppWizard-Generated Applications\
Bresenham

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

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

Web Browser Home Page and Search Page Modification

This backdoor modifies the Internet Explorer Zone Settings.

Other Details

This backdoor connects to the following possibly malicious URL:

  • http://bookfile.{BLOCKED}ng.com:443/{random hex values}
  • http://bookfile.{BLOCKED}ng.com:53/{random hex values}

  SOLUTION

Minimum Scan Engine:

9.750

FIRST VSAPI PATTERN FILE:

11.898.03

FIRST VSAPI PATTERN DATE:

04 Sep 2015

VSAPI OPR PATTERN File:

11.899.00

VSAPI OPR PATTERN Date:

05 Sep 2015

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

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

Step 3

Restart in Safe Mode

[ Learn More ]

Step 4

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_CURRENT_USER\Software
    • Local AppWizard-Generated Applications
  • In HKEY_CURRENT_USER\Software\Local AppWizard-Generated Applications
    • Bresenham
  • In HKEY_CURRENT_USER\Software\Local AppWizard-Generated Applications\Bresenham
    • Recent File List
  • In HKEY_CURRENT_USER\Software\Local AppWizard-Generated Applications\Bresenham
    • Settings

Step 5

Search and delete this file

[ Learn More ]
There may be some files that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the "More advanced options" option to include all hidden files and folders in the search result.  
  • %All Users Profile%\BaiduData\BaiduSkin.exe
  • %All Users Profile%\BaiduData\ImeSkin.dll
  • %All Users Profile%\BaiduData\BaiduUI.dll
  • %Startup%\BaiduSkin.lnk

Step 6

Reset Internet security settings

[ Learn More ]

Step 7

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