Modified by: Anthony Joe Melgarejo
ALIASES:

Trojan:Win32/Malagent (Microsoft), Trojan.Win32.Generic!BT (Sunbelt), BDS/Runner.as.2 (Antivir), BAT/Runner.AS!tr (Fortinet), Trojan.BAT.Runner (Ikarus), Win32/SecurityXploded.A (NOD32)

 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 as an attachment to email messages spammed by other malware/grayware or malicious users.

  TECHNICAL DETAILS

File Size: 3,666,616 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 11 Dec 2012

Arrival Details

This Trojan arrives as an attachment to email messages spammed by other malware/grayware or malicious users.

Installation

This Trojan adds the following folders:

  • {All User's Profile}\Msn
  • {All User's Profile}\Msn\Msn
  • %System Root%\users\public\Public Document
  • %ProgramData%\Msn
  • %ProgramData%\Msn\Msn

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.. %ProgramData% is a version of the Program Files folder where any user on a multi-user computer can make changes to programs. This is usually C:\ProgramData in Windows Vista and 7, or C:\Program Files on Windows 2000, XP (32-bit), and Server 2003, or C:\Program Files (x86) on Windows XP (64-bit).)

It drops the following files:

  • %System Root%\users\public\Public Document\bmsn.klm
  • %System Root%\users\public\Public Document\conf.reg
  • %System Root%\users\public\Public Document\dmsn.klm
  • %System Root%\users\public\Public Document\image viewer.exe
  • %System Root%\users\public\Public Document\keeprun.ini
  • %System Root%\users\public\Public Document\msn.lnk
  • %System Root%\users\public\Public Document\msnw.exe
  • %System Root%\users\public\Public Document\pic.bat
  • %System Root%\users\public\Public Document\pic.gif
  • %System Root%\users\public\Public Document\picture viewer.exe
  • %System Root%\users\public\Public Document\picture.bat
  • %System Root%\users\public\Public Document\SAM.bat
  • %System Root%\users\public\Public Document\statu.bat
  • %System Root%\users\public\Public Document\view.bat
  • %System Root%\users\public\Public Document\viewer.bat
  • {All User's Profile}\Msn\Msn\bmsn.klm
  • {All User's Profile}\Msn\Msn\conf.reg
  • {All User's Profile}\Msn\Msn\dmsn.klm
  • {All User's Profile}\Msn\Msn\image viewer.exe
  • {All User's Profile}\Msn\Msn\keeprun.ini
  • {All User's Profile}\Msn\Msn\msn.lnk
  • {All User's Profile}\Msn\Msn\msnw.exe
  • {All User's Profile}\Msn\Msn\pic.bat
  • {All User's Profile}\Msn\Msn\pic.gif
  • {All User's Profile}\Msn\Msn\picture viewer.exe
  • {All User's Profile}\Msn\Msn\picture.bat
  • {All User's Profile}\Msn\Msn\PIC_{random charecters}_ _{random numbers} .jpeg
  • {All User's Profile}\Msn\Msn\PIC_{random charecters}_ _{random numbers} .jpg
  • {All User's Profile}\Msn\Msn\SAM.bat
  • {All User's Profile}\Msn\Msn\statu.bat
  • {All User's Profile}\Msn\Msn\view.bat
  • {All User's Profile}\Msn\Msn\viewer.bat
  • {All User's Profile}\Start Menu\Programs\Startup\msn.lnk
  • %ProgramData%\Msn\Msn\bmsn.klm
  • %ProgramData%\Msn\Msn\conf.reg
  • %ProgramData%\Msn\Msn\dmsn.klm
  • %ProgramData%\Msn\Msn\image viewer.exe
  • %ProgramData%\Msn\Msn\keeprun.ini
  • %ProgramData%\Msn\Msn\msn.lnk
  • %ProgramData%\Msn\Msn\msnw.exe
  • %ProgramData%\Msn\Msn\pic.bat
  • %ProgramData%\Msn\Msn\pic.gif
  • %ProgramData%\Msn\Msn\picture viewer.exe
  • %ProgramData%\Msn\Msn\picture.bat
  • %ProgramData%\Msn\Msn\PIC_{random charecters}_ _{random numbers} .jpeg
  • %ProgramData%\Msn\Msn\PIC_{random charecters}_ _{random numbers} .jpg
  • %ProgramData%\Msn\Msn\SAM.bat
  • %ProgramData%\Msn\Msn\statu.bat
  • %ProgramData%\Msn\Msn\view.bat
  • %ProgramData%\Msn\Msn\viewer.bat

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.. %ProgramData% is a version of the Program Files folder where any user on a multi-user computer can make changes to programs. This is usually C:\ProgramData in Windows Vista and 7, or C:\Program Files on Windows 2000, XP (32-bit), and Server 2003, or C:\Program Files (x86) on Windows XP (64-bit).)

Autostart Technique

This Trojan creates the following registry entries to enable automatic execution of dropped component at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
stat = "{All Users' Profile}\Msn\Msn\statu.bat"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
stat2 = "{All Users' Profile}\Msn\Msn\statu.bat"

Other System Modifications

This Trojan adds the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\DomainProfile
EnableFirewall = "0"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\DomainProfile
DoNotAllowExceptions = "0"

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile
EnableFirewall = "0"

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

Other Details

This Trojan connects to the following possibly malicious URL:

  • ftp.{BLOCKED}stia.com

  SOLUTION

Minimum Scan Engine: 9.300
FIRST VSAPI PATTERN FILE: 9.588.03
FIRST VSAPI PATTERN DATE: 11 Dec 2012
VSAPI OPR PATTERN File: 9.589.00
VSAPI OPR PATTERN Date: 12 Dec 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

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
    • stat = "{All Users' Profile}\Msn\Msn\statu.bat"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • stat2 = "{All Users' Profile}\Msn\Msn\statu.bat"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\DomainProfile
    • EnableFirewall = "0"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\DomainProfile
    • DoNotAllowExceptions = "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_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile
    • From: EnableFirewall = "0"
      To: EnableFirewall = "1"

Step 5

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.
  • %ProgramData%\Msn
  • %System Root%\users\public\Public Document
  • {All User's Profile}\Msn

Step 6

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.
  • {All User's Profile}\Start Menu\Programs\Startup\msn.lnk

Step 7

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


Did this description help? Tell us how we did.