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TROJ_FAKEAV.MQH

October 09, 2012
 Analysis by: Mark Joseph Manahan
 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

 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.

It deletes itself after execution.

  TECHNICAL DETAILS

File Size:

409,600 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

05 Jul 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 a copy of itself in the following folders using different file names:

  • %System Root%\DOCUMENTS AND SETTINGS\ALL USERS\APPLICATION DATA\{random hex value}\{random hex value}.EXE

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

It adds the following possibly malicious files or file components:

  • %System Root%\DOCUMENTS AND SETTINGS\ALL USERS\APPLICATION DATA\{random hex value}\{random hex value}

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

It creates the following folders:

  • %System Root%\DOCUMENTS AND SETTINGS\ALL USERS\APPLICATION DATA\{random hex value}

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

Autostart Technique

This Trojan adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\RunOnce
{random hex value} = "%System Root%\Documents and Settings\All Users\Application Data\{random hex value}\{random hex value}.exe

Other Details

This Trojan connects to the following possibly malicious URL:

  • {BLOCKED}.{BLOCKED}.235.9

It deletes itself after execution.

  SOLUTION

Minimum Scan Engine:

9.200

FIRST VSAPI PATTERN FILE:

9.236.06

FIRST VSAPI PATTERN DATE:

05 Jul 2012

Step 1

For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

Restart in Safe Mode

[ Learn More ]

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\RunOnce
    • {random hex value} = "%System Root%\Documents and Settings\All Users\Application Data\{random hex value}\{random hex value}.exe"

Step 4

Search and delete this file

[ Learn More ]
There may be some component 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.
  • %System Root%\DOCUMENTS AND SETTINGS\ALL USERS\APPLICATION DATA\{random hex value}\{random hex value}

Step 5

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.  
  • %System Root%\DOCUMENTS AND SETTINGS\ALL USERS\APPLICATION DATA\{random hex value}

Step 6

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