TROJ_AGENT.BFGF

May 20, 2013
 ALIASES:

Trojan.Win32.Generic!BT (Sunbelt); Trojan horse SHeur4.BIHL (AVG)

 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:

11,776 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

20 May 2013

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:

  • %User Profile%\Xougjaa\Xougjaa.scr
  • %Program Files%\aimm\aimm.exe
  • %Program Files%\OPEN.scr

(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.. %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).)

It creates the following folders:

  • %User Profile%\Application Data\Xougjaa
  • %Program Files%\aimm

(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.. %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).)

Other System Modifications

This Trojan deletes the following files:

  • %Program Files%\OPEN.scr

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).)

It adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
WAVFile

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
WAVFile\Shell

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
WAVFile\Shell\Open

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
WAVFile\Shell\Open\
Command

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
JPGFile

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
JPGFile\Shell

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
JPGFile\Shell\Open

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
JPGFile\Shell\Open\
Command

HKEY_CLASSES_ROOT\.rar\ShellNew

HKEY_CLASSES_ROOT\.zip\ShellNew

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Classes
.txt = "TXTFile"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes
.mp3 = "MP3File"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes
.wma = "WMAFile"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes
.wav = "WAVFile"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes
.jpg = "JPGFile"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes
.png = "PNGFile"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes
.gif = "GIFFile"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
.rar\ShellNew
FileName = "%Program Files%\Gaaa5Na3.dat"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
.zip\ShellNew
FileName = "%Program Files%\Gaaa5Na3.dat"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
.zip\CompressedFolder\ShellNew
FileName = "%Program Files%\Gaaa5Na3.dat"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
%System%\ftp.exe = "%System%\ftp.exe:*:Enabled:winftpsvc"

It modifies the following registry entries:

HKEY_CURRENT_USER\Control Panel\Desktop
SCRNSAVE.EXE = "%User Profile%\Xougjaa\Xougjaa.scr"

(Note: The default value data of the said registry entry is %Windows%\system32\logon.scr.)

HKEY_CURRENT_USER\Control Panel\Desktop
ScreenSaveActive = "1"

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

HKEY_CURRENT_USER\Control Panel\Desktop
ScreenSaveTimeOut = "450"

(Note: The default value data of the said registry entry is 600.)

Dropping Routine

This Trojan drops the following files:

  • %User Profile%\Application Data\a.bat
  • %User Temp%\cab2
  • %User Temp%\cab3
  • %User Temp%\cab4
  • %User Temp%\cab5
  • %User Temp%\cab6
  • %User Temp%\cab7
  • %User Temp%\cab8
  • %Program Files%\Gaaa5Na3.dat
  • %User Temp%\cab9
  • %User Temp%\cab10
  • %User Temp%\cab11

(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.. %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.. %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).)

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.300

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

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\Classes
    • WAVFile
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\WAVFile
    • Shell
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\WAVFile\Shell
    • Open
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\WAVFile\Shell\Open
    • Command
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes
    • JPGFile
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\JPGFile
    • Shell
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\JPGFile\Shell
    • Open
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\JPGFile\Shell\Open
    • Command
  • In HKEY_CLASSES_ROOT\.rar
    • ShellNew
  • In HKEY_CLASSES_ROOT\.zip
    • ShellNew

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\Classes
    • .txt = "TXTFile"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes
    • .mp3 = "MP3File"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes
    • .wma = "WMAFile"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes
    • .wav = "WAVFile"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes
    • .jpg = "JPGFile"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes
    • .png = "PNGFile"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes
    • .gif = "GIFFile"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\.rar\ShellNew
    • FileName = "%Program Files%\Gaaa5Na3.dat"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\.zip\ShellNew
    • FileName = "%Program Files%\Gaaa5Na3.dat"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\.zip\CompressedFolder\ShellNew
    • FileName = "%Program Files%\Gaaa5Na3.dat"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
    • %System%\ftp.exe = "%System%\ftp.exe:*:Enabled:winftpsvc"

Step 4

Restore these modified registry values

[ Learn More ]

Important:Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator's help. You may also check out this Microsoft article first before modifying your computer's registry.

  • In HKEY_CURRENT_USER\Control Panel\Desktop
    • From: SCRNSAVE.EXE = "%User Profile%\Xougjaa\Xougjaa.scr"
      To: SCRNSAVE.EXE = ""%Windows%\system32\logon.scr""
  • In HKEY_CURRENT_USER\Control Panel\Desktop
    • From: ScreenSaveActive = "1"
      To: ScreenSaveActive = ""1""
  • In HKEY_CURRENT_USER\Control Panel\Desktop
    • From: ScreenSaveTimeOut = "450"
      To: ScreenSaveTimeOut = ""600""

Step 5

Search and delete these components

[ Learn More ]
There may be some components 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.
  • %User Profile%\Application Data\a.bat
  • %User Temp%\cab2
  • %User Temp%\cab3
  • %User Temp%\cab4
  • %User Temp%\cab5
  • %User Temp%\cab6
  • %User Temp%\cab7
  • %User Temp%\cab8
  • %Program Files%\Gaaa5Na3.dat
  • %User Temp%\cab9
  • %User Temp%\cab10
  • %User Temp%\cab11

Step 6

Search and delete these folders

[ 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.
  • %User Profile%\Application Data\Xougjaa
  • %Program Files%\aimm

Step 7

Scan your computer with your Trend Micro product to delete files detected as TROJ_AGENT.BFGF. 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 8

Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.

  • %Program Files%\OPEN.scr


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