ALIASES:

Trojan-PSW.Win32.Chisburg.ilo (Kaspersky); Trojan horse MSIL4.BTAD (AVG)

 PLATFORM:

Windows

 OVERALL RISK RATING:
 REPORTED INFECTION:
 SYSTEM IMPACT RATING:
 INFORMATION EXPOSURE:

  • Threat Type: Spyware

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This spyware 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: 502,784 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 04 Oct 2014

Arrival Details

This spyware 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 spyware drops the following copies of itself into the affected system:

  • %Program Files%\NAT Monitor\natmon.exe

(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 creates the following folders:

  • %User Profile%\Application Data\6ABCE574-4AFC-42C5-8AB9-5739A84D8A8B
  • %Program Files%\NAT Monitor
  • %User Profile%\6ABCE574-4AFC-42C5-8AB9-5739A84D8A8B\Logs
  • %User Profile%\Logs\Wilbert

(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).)

Autostart Technique

This spyware adds the following registry entries to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
NAT Monitor = "%Program Files%\NAT Monitor\natmon.exe"

Other System Modifications

This spyware modifies the following file(s):

  • %Application Data%\GDIPFONTCACHEV1.DAT

(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 deletes the following files:

  • {malware path and file name}:zone.identifier
  • %Program Files%\NAT Monitor\natmon.exe
  • %User Profile%\NAT Monitor\natmon.exe
  • %User Profile%\6ABCE574-4AFC-42C5-8AB9-5739A84D8A8B\settings.bak

(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).. %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.)

It modifies the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
GDIPlus
FontCachePath = "%Application Data%"

(Note: The default value data of the said registry entry is %User Profile%\Local Settings\Application Data.)

Dropping Routine

This spyware drops the following files:

  • %User Temp%\101451.jpg
  • %User Profile%\6ABCE574-4AFC-42C5-8AB9-5739A84D8A8B\run.dat
  • %User Profile%\6ABCE574-4AFC-42C5-8AB9-5739A84D8A8B\catalogue.dat
  • %User Profile%\6ABCE574-4AFC-42C5-8AB9-5739A84D8A8B\settings.bin

(Note: %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.. %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.)

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine: 9.700

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
    • NAT Monitor = "%Program Files%\NAT Monitor\natmon.exe"

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\Software\Microsoft\GDIPlus
    • From: FontCachePath = "%Application Data%"
      To: FontCachePath = ""%User Profile%\Local Settings\Application Data""

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 Temp%\101451.jpg
  • %User Profile%\6ABCE574-4AFC-42C5-8AB9-5739A84D8A8B\run.dat
  • %User Profile%\6ABCE574-4AFC-42C5-8AB9-5739A84D8A8B\catalogue.dat
  • %User Profile%\6ABCE574-4AFC-42C5-8AB9-5739A84D8A8B\settings.bin

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\6ABCE574-4AFC-42C5-8AB9-5739A84D8A8B
  • %Program Files%\NAT Monitor
  • %User Profile%\6ABCE574-4AFC-42C5-8AB9-5739A84D8A8B\Logs
  • %User Profile%\Logs\Wilbert

Step 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TSPY_KEYLOG.XTRX. 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 deleted/modified files and/or registry entries from backup

*Note: Only Microsoft-related files/keys/values will be restored. If this malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.

    • %Application Data%\GDIPFONTCACHEV1.DAT

Step 9

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.

  • {malware path and file name}:zone.identifier
  • %Program Files%\NAT Monitor\natmon.exe
  • %User Profile%\NAT Monitor\natmon.exe
  • %User Profile%\6ABCE574-4AFC-42C5-8AB9-5739A84D8A8B\settings.bak


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