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TROJ_FAKEAV.MAD

June 04, 2013
 Analysis by: Merianne Polintan
 ALIASES:

Mal/FakeAV-CZ(Sophos), Trojan horse Generic18.FKJ(AVG), W32/FakeAV.ACK (exact)(Fprot), Trojan W32/Winwebsec.Q(Norman), Adware.SecurityTool(VBA32)

 PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

 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 the initially executed copy of itself.

  TECHNICAL DETAILS

File Size:

832,001 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

01 Jul 2010

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 adds the following folders:

  • %All Users Profile%\Application Data\{Random Numbers}

(Note: %All Users Profile% is the All Users or Common profile folder, which is C:\Documents and Settings\All Users in Windows 2000, XP, and Server 2003, and C:\ProgramData in Windows Vista and 7.)

It drops the following copies of itself into the affected system and executes them:

  • %All Users Profile%\Application Data\{ Random Numbers}\{Random Numbers}.exe

(Note: %All Users Profile% is the All Users or Common profile folder, which is C:\Documents and Settings\All Users in Windows 2000, XP, and Server 2003, and C:\ProgramData in Windows Vista and 7.)

It drops the following files:

  • %All Users Profile%\Application Data\{Random Numbers}\{Random Numbers}.bat

(Note: %All Users Profile% is the All Users or Common profile folder, which is C:\Documents and Settings\All Users in Windows 2000, XP, and Server 2003, and C:\ProgramData in Windows Vista and 7.)

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 Numbers} = "%All Users Profile%\Application Data\{Random Numbers}\{Random Numbers}.exe

It drops the following shortcut pointing to its copy in the User Startup folder to enable its automatic execution at every system startup:

  • %Start Menu%\Programs\Security Tool.Lnk
  • %Desktop%\Security Tool.Lnk

(Note: %Start Menu% is the current user's Start Menu folder, which is usually C:\Windows\Start Menu or C:\Documents and Settings\{User name}\Start Menu on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming\Microsoft\Windows\Start Menu on Windows Vista and 7.. %Desktop% is the current user's desktop, which is usually C:\Documents and Settings\{User Name}\Desktop on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\Desktop on Windows Vista and 7.)

Other System Modifications

This Trojan adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\{Random Numbers}

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\{Random Numbers}
Grep = "{Random Hex Values}"

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://{BLOCKED}.{BLOCKED}.60.126/set.php?url={Value}
  • http://{BLOCKED}twebcenter.com/

It deletes the initially executed copy of itself

  SOLUTION

Minimum Scan Engine:

9.300

FIRST VSAPI PATTERN FILE:

7.278.12

FIRST VSAPI PATTERN DATE:

01 Jul 2010

VSAPI OPR PATTERN File:

7.279.00

VSAPI OPR PATTERN Date:

02 Jul 2010

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

Restart in Safe Mode

[ Learn More ]

Step 3

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.  
  • %All Users Profile%\Application Data\{Random Numbers}

Step 4

Search and delete these files

[ 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.
  • %Start Menu%\Programs\Security Tool.Lnk
  • %Desktop%\Security Tool.Lnk

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
    • {Random Numbers}

 

Step 6

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 Numbers} = "%All Users Profile%\Application Data\{Random Numbers}\{Random Numbers}.exe

Step 7

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