VBS_FAKEANTIV.SM

 Analysis by: Rika Joi Gregorio

 ALIASES:

Worm:VBS/Slogod.L(Microsoft), VBS/Autorun.worm.k(McAfee), VBS/AutoRun.DX worm(Eset)

 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:
 INFORMATION EXPOSURE:

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This worm arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

  TECHNICAL DETAILS

File Size:

32,844 bytes

File Type:

VBS

Memory Resident:

Yes

Initial Samples Received Date:

01 Sep 2012

Arrival Details

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

  • %System%\FAantivirus.vbs

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)

Autostart Technique

This worm modifies the following registry entries to ensure it automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Userinit = "%System%\userinit.exe,%System%\wscript.exe %System%\FAantivirus.vbs"

(Note: The default value data of the said registry entry is "%System%\userinit.exe,".)

Other System Modifications

This worm adds the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System

HKEY_CURRENT_USER\Software\Policies\
Microsoft\Windows

HKEY_CURRENT_USER\Software\Policies\
Microsoft\Windows\System

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
Window Title = "Fusion|Ace Enterprises"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
DisableTaskMgr = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
DisableRegistryTools = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
NoFolderOptions = "0"

HKEY_CURRENT_USER\Software\Policies\
Microsoft\Windows\System
DisableCMD = "0"

It modifies the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
Start Page = "http://www.socio.fusionace.com"

(Note: The default value data of the said registry entry is "{Default start page}".)

Propagation

This worm drops the following copy(ies) of itself in all removable drives:

  • {Drive Letter}:\FAantivirus.vbs

It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

The said .INF file contains the following strings:

[autorun]
open=wscript.exe FAantivirus.vbs
icon=%System%\SHELL32.dll,8
action=Open folder to view files
shell\open=Open
shell\open\Command=wscript.exe FAantivirus.vbs
shell\Auto=AutoPlay
shell\Auto\Command=wscript.exe FAantivirus.vbs
shell\Explore\Command=wscript.exe FAantivirus.vbs
shell\Find=Search...
shell\Find\Command=wscript.exe FAantivirus.vbs
shell\Format...=Format...
shell\Format...\Command=wscript.exe FAantivirus.vbs

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)

  SOLUTION

Minimum Scan Engine:

9.300

VSAPI OPR PATTERN File:

9.109.00

VSAPI OPR PATTERN Date:

15 May 2012

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

Identify and delete files detected as VBS_FAKEANTIV.SM using either the Startup Disk or Recovery Console

[ 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\Internet Explorer\Main
    • Window Title = "Fusion|Ace Enterprises"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System
    • DisableTaskMgr = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System
    • DisableRegistryTools = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System
    • NoFolderOptions = "0"
  • In HKEY_CURRENT_USER\Software\Policies\Microsoft\Windows\System
    • DisableCMD = "0"

Step 4

Restore this modified 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\Internet Explorer\Main
    • From: Start Page = "http://www.socio.fusionace.com"
      To: Start Page = "{Default start page}"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
    • From: Userinit = "%System%\userinit.exe,%System%\wscript.exe %System%\FAantivirus.vbs"
      To: Userinit = "%System%\userinit.exe,"

Step 5

Search and delete AUTORUN.INF files created by VBS_FAKEANTIV.SM that contain these strings

[ Learn More ]


[autorun]
open=wscript.exe FAantivirus.vbs
icon=%System%\SHELL32.dll,8
action=Open folder to view files
shell\open=Open
shell\open\Command=wscript.exe FAantivirus.vbs
shell\Auto=AutoPlay
shell\Auto\Command=wscript.exe FAantivirus.vbs
shell\Explore\Command=wscript.exe FAantivirus.vbs
shell\Find=Search...
shell\Find\Command=wscript.exe FAantivirus.vbs
shell\Format...=Format...
shell\Format...\Command=wscript.exe FAantivirus.vbs

Step 6

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