Analysis by: Roland Marco Dela Paz
 PLATFORM:

Windows 2000, XP, Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  TECHNICAL DETAILS

File Size: 194,560 bytes
File Type: PE
Memory Resident: Yes
Initial Samples Received Date: 15 Dec 2009
Payload: Terminates processes

Installation

This Trojan adds the following folders:

  • %Application Data%\{random CLSID for Firefox}
  • %Application Data%\{random CLSID for Firefox}\chrome
  • %Application Data%\{random CLSID for Firefox}\chrome\content

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Windows\Profiles\{user name}\Application Data on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Application Data on Windows NT, and C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, XP, and Server 2003.)

It drops the following files:

  • %Application Data%\{random CLSID for Firefox}\chrome.manifest - non-malicious component
  • %Application Data%\{random CLSID for Firefox}\install.rdf - non-malicious component
  • %Application Data%\{random CLSID for Firefox}\chrome\content\_cfg.js - non-malicious component
  • %Application Data%\{random CLSID for Firefox}\chrome\content\overlay.xul - non-malicious component

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Windows\Profiles\{user name}\Application Data on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Application Data on Windows NT, and C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, XP, and Server 2003.)

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
{random} = rundll32.exe "{malware path and file name}",Startup

Other System Modifications

This Trojan adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\{random key}

It adds the following registry entries as part of its installation routine:

HKEY_LOCAL_MACHINE\SOFTWARE\Mozilla\
Firefox\Extensions
{random CLSID for Firefox} = %Application Data%\{random CLSID for Firefox}

Process Termination

This Trojan terminates the following processes if found running in the affected system's memory:

  • mrt.exe

  SOLUTION

Minimum Scan Engine: 8.900
FIRST VSAPI PATTERN FILE: 6.694.04
FIRST VSAPI PATTERN DATE: 15 Dec 2009
VSAPI OPR PATTERN File: 7.536.03
VSAPI OPR PATTERN Date: 13 Oct 2010
OPP PATTERN File: 7.537.00
OPP PATTERN Date: 13 Oct 2010

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

Scan your computer with your Trend Micro product and note files detected as TROJ_MUFANOM.BQ

Step 3

Restart in Safe Mode

[ Learn More ]

Step 4

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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • {random} = rundll32.exe {malware path and file name},Startup
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Mozilla\Firefox\Extensions
    • {random CLSID for Firefox} = %Application Data%\{random CLSID for Firefox}

Step 5

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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion
    • {random key}

Step 6

Search and delete this folder

[ 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.
  •  %Application Data%\{random CLSID for Firefox}

Step 7

Search and delete the file detected as TROJ_MUFANOM.BQ

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden files in the search result.


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