Analysis by: Marfel Tiamzon

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Spyware

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

This spyware attempts to steal sensitive online banking information, such as user names and passwords. This routine risks the exposure of the user's account information, which may then lead to the unauthorized use of the stolen data.

It checks for the presence of the following processes which are related to Outpost Personal Firewall and ZoneLabs Firewall Client:

  • outpost.exe
  • zlclient.exe

It terminates if either of the said processes exist. This is to ensure that it runs uninterrupted. It also has rootkit capabilities, which enables it to hide its processes and files from the user.

  TECHNICAL DETAILS

File Size: 153,088 bytes
File Type: PE
Memory Resident: Yes
Initial Samples Received Date: 12 Oct 2010

Installation

This spyware then creates the following non-malicious file(s):

  • %System%\wsnpoem\audio.dll
  • %User Profile%\Application Data\wsnpoem\audio.dll

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.. %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 creates the following folders with attributes set to System and Hidden to prevent users from discovering and removing its components:

  • %System%\wsnpoem
  • %User Profile%\Application Data\wsnpoem

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.. %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 adds the following mutexes to ensure that only one of its copies runs at any one time:

  • __SYSTEM__64AD0625__

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

  • SVCHOST.EXE
  • WINLOGON.EXE

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Userinit = %System%\userinit.exe, %System%\ntos.exe,

(Note: The default value data of the said registry entry is %System\Userinit.exe,.)

Other System Modifications

This spyware also creates the following registry entry(ies) as part of its installation routine:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Network
UID = {Computer name}_{Random numbers}

HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\Network
UID = {Computer name}_{Random numbers}

Information Theft

This spyware attempts to steal sensitive online banking information, such as user names and passwords. This routine risks the exposure of the user's account information, which may then lead to the unauthorized use of the stolen data.

Other Details

This spyware checks for the presence of the following processes which are related to Outpost Personal Firewall and ZoneLabs Firewall Client:

  • outpost.exe
  • zlclient.exe

It terminates if either of the said processes exist. This is to ensure that it runs uninterrupted. It also has rootkit capabilities, which enables it to hide its processes and files from the user.

It did not exhibit backdoor routines during testing.

  SOLUTION

Minimum Scan Engine: 8.900

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

Identify and delete files detected as TSPY_ZBOT.PB using either the Startup Disk or Recovery Console

[ 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 NT\CurrentVersion\Network
    • UID = {Computer name}_{Random numbers}
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Network
    • UID = {Computer name}_{Random numbers}

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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
    • From: Userinit = %System%\userinit.exe, %System%\ntos.exe,
      To: %System\Userinit.exe,

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.
  • In %System%\wsnpoem
    • %User Profile%\Application Data\wsnpoem

Step 6

Scan your computer with your Trend Micro product to delete files detected as TSPY_ZBOT.PB. 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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