Analysis by: Jaime Benigno Reyes
ALIASES:

Trojan:Win32/Weelsof.C (Microsoft), Trojan.Win32.Weelsof.aem (Kaspersky)

 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: 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: Varies
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 06 Feb 2012

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.

Installation

This Trojan drops the following files:

  • %ProgramData%\{15 random letters} (Windows Vista and 7 only)
  • %System Root%\Users\All Users\{15 random letters} (Windows Vista and 7 only)
  • %System Root%\Documents and Settings\All Users\Application Data\{15 random letters} (versions other than Windows Vista and 7)

(Note: %ProgramData% is a version of the Program Files folder where any user on a multi-user computer can make changes to programs. This is usually C:\ProgramData in Windows Vista and 7, or C:\Program Files on Windows 2000, XP (32-bit), and Server 2003, or C:\Program Files (x86) on Windows XP (64-bit).. %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://{BLOCKED}abibi.jennpearce.com
  • http://{BLOCKED}mhwrhlzzkxhgwsdhvvs.info

  SOLUTION

Minimum Scan Engine: 9.300
FIRST VSAPI PATTERN FILE: 9.708.09
FIRST VSAPI PATTERN DATE: 06 Feb 2013
VSAPI OPR PATTERN File: 9.709.00
VSAPI OPR PATTERN Date: 06 Feb 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

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.  
  • %ProgramData%\{15 random letters}  (Windows Vista and 7 only)
  • %System Root%\Users\All Users\{15 random letters} (Windows Vista and 7 only)
  • %System Root%\Documents and Settings\All Users\Application Data\{15 random letters} (versions other than Windows Vista and 7)

Step 4

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