Analysis by: Sabrina Lei Sioting
 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: 522,240 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 16 Apr 2009

Installation

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

  • %Application Data%\hotfix.exe

(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 5-numbers}.bat

(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_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\Winlogon
Shell = %Application Data%\hotfix.exe

Rogue Antivirus Routine

This Trojan displays the following fake alerts:

  • Fake alert window

  SOLUTION

Minimum Scan Engine: 8.900
VSAPI PATTERN File: 07.568.16
VSAPI PATTERN Date: 26 Oct 2010
VSAPI PATTERN Date: 10/26/2010 12:00:00 AM
FIRST VSAPI PATTERN FILE: 5.970.09
FIRST VSAPI PATTERN DATE: 16 Apr 2009
VSAPI OPR PATTERN File: 7.573.00
VSAPI OPR PATTERN Date: 27 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

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 NT\CurrentVersion\Winlogon
    • Shell = %Application Data%\hotfix.exe

Step 3

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. %Application Data%\{random 5-numbers}.bat

Step 4

Scan your computer with your Trend Micro product to delete files detected as TROJ_FAKEAV.DAL. 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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