Analysis by: Kathleen Notario
 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

  OVERVIEW

This Trojan deletes itself after execution.

  TECHNICAL DETAILS

File Size: 39,424 bytes
File Type: PE
Memory Resident: Yes
Initial Samples Received Date: 27 Oct 2010

Installation

This Trojan drops the following copies of itself into the affected system:

  • %System%\{random filename}.exe

(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)

It deletes itself after execution.

Autostart Technique

This Trojan registers as a system service to ensure its automatic execution at every system startup by adding the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Transaction
ImagePath = %System%\{random filename}.exe

Dropping Routine

This Trojan drops the following files:

  • %System%\hra33.dll - detected as TROJ_FAKELPK.C

(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)

  SOLUTION

Minimum Scan Engine: 8.900
VSAPI PATTERN File: 7.571.00
VSAPI PATTERN Date: 27 Oct 2010
VSAPI PATTERN Date: 10/27/2010 12:00:00 AM

Step 1

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

Step 2

Remove malware files dropped/downloaded by TROJ_MICROFAK.AC

     TROJ_FAKELPK.C

Step 3

Restart in Safe Mode

[ Learn More ]

Step 4

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\SYSTEM\CurrentControlSet\Services
    • Transaction

Step 5

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