Analysis by: Marfel Tiamzon
 PLATFORM:

Windows 98, ME, NT, 2000, XP, Server 2003

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

It opens a hidden explorer.exe and calc.exe.

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.

It opens a hidden Internet Explorer window.

  TECHNICAL DETAILS

File Size: 696,128 b bytes
Memory Resident: Yes

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:

  • %Program Files%\_ksStation.exe
  • %Program Files%\Common Files\Microsoft Shared\MSInfo\ksStation.exe

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files.)

It injects itself into the following processes running in the affected system's memory:

  • iexplore.exe
  • calc.exe

Autostart Technique

This Trojan registers itself as a system service to ensure its automatic execution at every system startup by adding the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Windows_ksStation
=

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

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Windows_ksStation
Type = 110

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Windows_ksStation
Start = 2

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Windows_ksStation
ErrorControl = 0

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Windows_ksStation
ImagePath = %Program Files%\Common Files\Microsoft Shared\MSINFO\ksStation.exe

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Windows_ksStation
DisplayName = Windows_ksStation

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Windows_ksStation\Security
=

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Windows_ksStation\Security
Security = {hex values}

Other Details

This Trojan opens a hidden Internet Explorer window.

It opens the following applications:

  • calc.exe

  SOLUTION

Minimum Scan Engine: 8.900

Step 1

For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

Restart in Safe Mode

[ Learn More ]

Step 3

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\SYSTEM\CurrentControlSet\Services\
    • Windows_ksStation
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Windows_ksStation
    • Type=110
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Windows_ksStation
    • Start=2
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Windows_ksStation
    • ErrorControl=0
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Windows_ksStation
    • ImagePath=%Program Files%\Common Files\Microsoft Shared\MSINFO\ksStation.exe
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Windows_ksStation
    • DisplayName=Windows_ksStation
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Windows_ksStation\
    • Security
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Windows_ksStation\Security
    • Security={hex values}

Step 4

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