TROJ_FAKEAV.GSI

 Analysis by: Cris Nowell Pantanilla

 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.

  TECHNICAL DETAILS

File Size:

455,680 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

28 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:

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

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}.exe = "%Documents and Settings%\All Users\Application Data\{random}.exe"

Other System Modifications

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Start_ShowNetConn = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Start_ShowNetPlaces = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
ActiveDesktop
HidNoChangingWallPaperden = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Attachments
SaveZoneInformation = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
DisableTaskMgr = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer
NoDesktop = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer
EnableAutoTray = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
TaskbarGlomLevel = "2"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Start_ShowUser = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Start_ShowControlPanel = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Start_ShowHelp = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Start_ShowMyComputer = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Start_ShowMyDocs = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Start_ShowMyMusic = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Start_ShowMyGames = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Start_ShowMyPics = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Start_ShowPrinters = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Start_ShowRun = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Start_ShowSearch = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Start_ShowSetProgramAccessAndDefaults = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings
PrivDiscUiShown = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
system
DisableTaskMgr = "1"

It modifies the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Desktop\Components
GeneralFlags = "0"

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Hidden = "0"

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
ShowSuperHidden = "0"

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Start_ShowRecentDocs = "0"

(Note: The default value data of the said registry entry is "2".)

Other Details

This Trojan connects to the following possibly malicious URL:

  • {BLOCKED}comprse.com
  • {BLOCKED}eward.com
  • {BLOCKED}nacalin.com
  • {BLOCKED}ueredir.com
  • {BLOCKED}iolocen.com

NOTES:

It changes the attributes of all files in the system to System and Hidden.

  SOLUTION

Minimum Scan Engine:

9.200

FIRST VSAPI PATTERN FILE:

8.870.04

FIRST VSAPI PATTERN DATE:

28 Mar 2012

VSAPI OPR PATTERN File:

8.871.00

VSAPI OPR PATTERN Date:

29 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

Restart in Safe Mode

[ 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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • {random}.exe = "%Documents and Settings%\All Users\Application Data\{random}.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • Start_ShowNetConn = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • Start_ShowNetPlaces = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\ActiveDesktop
    • HidNoChangingWallPaperden = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Attachments
    • SaveZoneInformation = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System
    • DisableTaskMgr = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer
    • NoDesktop = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer
    • EnableAutoTray = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • TaskbarGlomLevel = "2"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • Start_ShowUser = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • Start_ShowControlPanel = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • Start_ShowHelp = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • Start_ShowMyComputer = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • Start_ShowMyDocs = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • Start_ShowMyMusic = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • Start_ShowMyGames = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • Start_ShowMyPics = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • Start_ShowPrinters = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • Start_ShowRun = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • Start_ShowSearch = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • Start_ShowSetProgramAccessAndDefaults = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings
    • PrivDiscUiShown = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\system
    • DisableTaskMgr = "1"

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\Desktop\Components
    • From: GeneralFlags = "0"
      To: GeneralFlags = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: Hidden = "0"
      To: Hidden = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: ShowSuperHidden = "0"
      To: ShowSuperHidden = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: Start_ShowRecentDocs = "0"
      To: Start_ShowRecentDocs = "2"

Step 5

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

Step 6

  1. Open a command prompt.
    • For Windows 2000, Windows XP, and Windows Server 2003 users, click Start>Run. In the Open input box, type CMD then press Enter.
  2. In the CMD console, type the following:

    ATTRIB [+R | -R] [+A | -A ] [+S | -S] [+H | -H] [+I | -I] [drive:][path][file name] [/S [/D] [/L]]

    Where:
    + Sets an attribute.
    - Clears an attribute
    R Read-only file attribute
    A Archive file attribute
    S System file attribute
    H Hidden file attribute
    I Not content indexed file attribute
    [drive:][path][filename]
    Specifies a file or files for attrib to process
    /S Processes matching files in the current folder and all subfolders.
    /D Processes folders
    /L Work on the attributes of the Symbolic Link versus the target of the Symbolic Link
    Example:
    To unhide all files and folders (including subfolders) in drive D:
    ATTRIB –H D:\* /S /D
  3. Repeat Step 2 for folders and files in other drives or directories.


Did this description help? Tell us how we did.