Analysis by: Abraham Latimer Camba

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

 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 connects to certain URLs. It may do this to remotely inform a malicious user of its installation. It may also do this to download possibly malicious files onto the computer, which puts the computer at a greater risk of infection by other threats.

It deletes the initially executed copy of itself.

  TECHNICAL DETAILS

File Size: 361,984 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 26 Mar 2012

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

  • %System Root%\Documents and Settings\All Users\Application Data\{random name}.exe

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

It drops the following files:

  • %Desktop%\System Check.lnk
  • %Start Menu%\Programs\System Check\System Check.lnk
  • %Start Menu%\Programs\System Check\Uninstall System Check.lnk
  • %System Root%\Documents and Settings\All Users\Application Data\{random name}
  • %User Profile%\Application Data\Microsoft\Internet Explorer\Quick Launch\System Check.lnk

(Note: %Desktop% is the current user's desktop, which is usually C:\Windows\Profiles\{user name}\Desktop on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Desktop on Windows NT, and C:\Documents and Settings\{User Name}\Desktop on Windows 2000, XP, and Server 2003.. %Start Menu% is the current user's Start Menu folder, which is usually C:\Windows\Profiles\{user name}\Start Menu on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu on Windows NT and C:\Windows\Start Menu or C:\Documents and Settings\{User name}\Start Menu on Windows 2000, XP, and Server 2003.. %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.. %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)

It creates the following folders:

  • %Start Menu%\Programs\System Check

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

Other System Modifications

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

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
Use FormSuggest = "Yes"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings
WarnOnZoneCrossing = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings
WarnonBadCertRecving = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings
CertificateRevocation = "0"

It modifies the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\3
1601 = "0"

(Note: The default value data of the said registry entry is 1.)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\WinTrust\
Trust Providers\Software Publishing
State = "23e00"

(Note: The default value data of the said registry entry is 23c00.)

Download Routine

This Trojan connects to the following malicious URLs:

  • {BLOCKED}.{BLOCKED}.13.19
  • {BLOCKED}ward.com
  • {BLOCKED}ward.com/britix/a
  • {BLOCKED}ward.com/britix/ar
  • {BLOCKED}ward.com/up.php?0Q9oBPXEN0uECUgzEJ95RQsajjnvq1aG3F/2q5oNvBGAyHya0iCkBIHoIxsgj7n41ezh
  • {BLOCKED}sprin.com
  • {BLOCKED}locen.com
  • {BLOCKED}locen.com/britix/a
  • {BLOCKED}locen.com/customers/buy.php?pid=DEFRAG_ADV_BASIC&id=543&subid=01&guid=333470043334410233344203&version_name=System%20Check
  • {BLOCKED}redir.com

Other Details

This Trojan deletes the initially executed copy of itself

  SOLUTION

Minimum Scan Engine: 9.200
FIRST VSAPI PATTERN FILE: 8.866.03
FIRST VSAPI PATTERN DATE: 27 Mar 2012
VSAPI OPR PATTERN File: 8.867.00
VSAPI OPR PATTERN Date: 27 Mar 2012

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_FAKEAV.GRO

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_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
    • Use FormSuggest = "Yes"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings
    • WarnOnZoneCrossing = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings
    • WarnonBadCertRecving = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings
    • CertificateRevocation = "0"

Step 5

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\Windows\CurrentVersion\Internet Settings\Zones\3
    • From: 1601 = "0"
      To: 1601 = 1
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\WinTrust\Trust Providers\Software Publishing
    • From: State = "23e00"
      To: State = 23c00

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.
  • %Start Menu%\Programs\System Check

Step 7

Search and delete these files

[ 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.
  • %Desktop%\System Check.lnk
  • %Start Menu%\Programs\System Check\System Check.lnk
  • %Start Menu%\Programs\System Check\Uninstall System Check.lnk
  • %System Root%\Documents and Settings\All Users\Application Data\{random name}
  • %User Profile%\Application Data\Microsoft\Internet Explorer\Quick Launch\System Check.lnk

Step 8

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