Analysis by: Francis Xavier Antazo
ALIASES:

Trojan:Win32/Miuref (Microsoft), Win32/Boaxxe.BR (ESET)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet, Dropped by other malware

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.

It requires its main component to successfully perform its intended routine.

  TECHNICAL DETAILS

File Size: 142,392 bytes
Memory Resident: Yes
Initial Samples Received Date: 21 Mar 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.

Installation

This Trojan drops the following files:

  • %AppDataLocal%\Mozilla\Firefox\Profiles\[random characters].default\extensions\[random characters]\chrome.manifest
  • %AppDataLocal%\Mozilla\Firefox\Profiles\[random characters].default\extensions\[random characters]\install.rdf

(Note: %AppDataLocal% is the Application Data folder found in Local Settings, where it is usually C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local 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 Trojan adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
[random characters] = "regsvr32.exe %AppDataLocal%\[random characters](variable 1)\random characters"

Other Details

This Trojan requires its main component to successfully perform its intended routine.

NOTES:

variable 1 may have the following values:

  • works
  • tion
  • soft
  • ics
  • media
  • Pack

It reports the following information of the affected system:

  • OS version
  • processor information

It tries to report its infection to the following URL:

  • {BLOCKED}.{BLOCKED}.112.229

  SOLUTION

Minimum Scan Engine: 9.750
FIRST VSAPI PATTERN FILE: 11.620.04
FIRST VSAPI PATTERN DATE: 16 Apr 2015
VSAPI OPR PATTERN File: 11.621.00
VSAPI OPR PATTERN Date: 17 Apr 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

Delete this registry value

[ 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\Microsoft\Windows\CurrentVersion\Run
    • [random characters] = "regsvr32.exe %AppDataLocal%\[random characters](variable 1)\random characters"

Step 4

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.  
  • %AppDataLocal%\Mozilla\Firefox\Profiles\[random characters].default\extensions\[random characters]\chrome.manifest
  • %AppDataLocal%\Mozilla\Firefox\Profiles\[random characters].default\extensions\[random characters]\install.rdf

Step 5

Scan your computer with your Trend Micro product to delete files detected as TROJ_BOAXXE.TMC. 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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