Analysis by: RonJay Kristoffer Caragay
 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This Trojan 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: 213,492 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 20 Aug 2015

Arrival Details

This Trojan 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 Trojan drops the following files:

  • %User Startup%\system.pif

(Note: %User Startup% is the current user's Startup folder, which is usually C:\Documents and Settings\{user}\Start Menu\Programs\Startup on Windows 2000 and XP, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows Vista, 7, and 8.)

Dropping Routine

This Trojan drops the following files:

  • %All Users Profile%\cert{value}.der

(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.)

Download Routine

This Trojan saves the files it downloads using the following names:

  • %All Users Profile%\Microsoft-KB{random}.exe
    or
  • %All Users Profile%\WindowsXP-KB{random}.exe

(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 Details

This Trojan connects to the following possibly malicious URL:

  • http://www.{BLOCKED}unter.com/counter.php?vtrtvrvtrtvertvr
  • http://www.{BLOCKED}unter.com/counter.php?tcrcrcerererwbvbbrtdf
  • http://www.{BLOCKED}zerhof-wetzikon.ch/images/rtucrtmirumctrutbitueriumxe/ivotyimoyctorieotcmir.exe

  SOLUTION

Minimum Scan Engine: 9.750
FIRST VSAPI PATTERN FILE: 11.866.03
FIRST VSAPI PATTERN DATE: 20 Aug 2015
VSAPI OPR PATTERN File: 11.867.00
VSAPI OPR PATTERN Date: 21 Aug 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

Search and delete these files

[ 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%\Microsoft-KB{random}.exe
  • %All Users Profile%\WindowsXP-KB{random}.exe
  • %User Startup%\system.pif
  • %All Users Profile%\cert{value}.der

Step 5

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