Analysis by: Abraham Latimer Camba
 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: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel: Dropped by other malware, Downloaded from the Internet

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.

However, as of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size: 6,656 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 20 Apr 2013
Payload: Connects to URLs/IPs, Collects system information, Downloads files

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 adds the following folders:

  • %Application Data%\Theme
  • %Program Files%\Messenger\Theme

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming 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 drops the following copies of itself into the affected system and executes them:

  • %Application Data%\Theme\msmsgs.exe
  • %Program Files%\Messenger\Theme\msmsgs.exe

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming 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 drops the following file(s)/component(s):

  • %Application Data%\msgslang.db - blob file containing malware routines

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.)

It adds the following processes:

  • iexplore.exe

It injects itself into the following processes as part of its memory residency routine:

  • iexplore.exe

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
User Shell Folders
Startup = "%Application Data%\Theme"

(Note: The default value data of the said registry entry is %USERPROFILE%\Start Menu\Programs\Startup.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
User Shell Folders
Common Startup = "%Program Files%\Messenger\Theme"

(Note: The default value data of the said registry entry is %ALLUSERSPROFILE%\Start Menu\Programs\Startup.)

Other Details

This Trojan attempts to access the following websites to download files, which are possibly malicious:

  • {BLOCKED}olf.{BLOCKED}p.net

However, as of this writing, the said sites are inaccessible.

  SOLUTION

Minimum Scan Engine: 9.300
FIRST VSAPI PATTERN FILE: 9.868.01
FIRST VSAPI PATTERN DATE: 20 Apr 2013
VSAPI OPR PATTERN File: 9.869.00
VSAPI OPR PATTERN Date: 21 Apr 2013

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

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\Explorer\User Shell Folders
    • From: Startup = "%Application Data%\Theme"
      To: Startup = %USERPROFILE%\Start Menu\Programs\Startup
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\User Shell Folders
    • From: Common Startup = "%Program Files%\Messenger\Theme"
      To: Common Startup = %ALLUSERSPROFILE%\Start Menu\Programs\Startup

Step 4

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.
  • %Application Data%\Theme
  • %Program Files%\Messenger\Theme

Step 5

Search and delete this file

[ 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.
  • %Application Data%\msgslang.db

Step 6

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