Analysis by: Erika Bianca Mendoza

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

This Trojan may be downloaded by other malware/grayware/spyware from remote sites. It may be dropped by other malware. It may be unknowingly downloaded by a user while visiting malicious websites.

It uses Windows Task Scheduler to create a scheduled task that executes the dropped copy.

  TECHNICAL DETAILS

File Size: Varies
File Compression: UPX
Memory Resident: Yes
Initial Samples Received Date: 17 Mar 2011

Arrival Details

This Trojan may be downloaded by other malware/grayware/spyware from remote sites.

It may be dropped by other malware.

It may be unknowingly downloaded by a user while visiting malicious websites.

Installation

This Trojan drops the following files:

  • %Windows%\Tasks\{62C40AA6-4406-467a-A5A5-DFDF1B559B7A}.job

(Note: %Windows% is the Windows folder, which is usually C:\Windows.)

It drops the following copies of itself into the affected system:

  • %Windows%\Cgowua.exe

(Note: %Windows% is the Windows folder, which is usually C:\Windows.)

It uses Windows Task Scheduler to create a scheduled task that executes the dropped copy.

It adds the following mutexes to ensure that only one of its copies runs at any one time:

  • Global\{C814BC71-BD20-47f7-8107-9BCB142C6F1C}

Other System Modifications

This Trojan adds the following registry keys:

HKEY_CURRENT_USER\Software\2SPI9KEA4C

It adds the following registry entries as part of its installation routine:

HKEY_CURRENT_USER\Software\2SPI9KEA4C
CfiD = dword:00000005

HKEY_CURRENT_USER\Software\2SPI9KEA4C
Cfi3 = dword:01cbe836

HKEY_CURRENT_USER\Software\2SPI9KEA4C
CfiE = dword:b43f5ac0

HKEY_CURRENT_USER\Software\2SPI9KEA4C
Cku2 = {encrypted data}

HKEY_CURRENT_USER\Software\2SPI9KEA4C
CfiK = dword:00000679

HKEY_CURRENT_USER\Software\2SPI9KEA4C
Cfi2 = dword:00000001

HKEY_CURRENT_USER\Software\2SPI9KEA4C
CfiE3 = dword:00000001

HKEY_CURRENT_USER\Software\2SPI9KEA4C
CfiE3 = dword:00000001

HKEY_CURRENT_USER\Software\2SPI9KEA4C
Cku9 = {encrypted data}

HKEY_CURRENT_USER\Software\2SPI9KEA4C
Cku4 = {encrypted data}

  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

Terminate a process file/s detected as TROJ_KRYPTIK.SM7

[ Learn More ]

*Note: If the detected file/s is/are not displayed in theWindows Task Manager, continue doing the next steps.

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_CURRENT_USER\Software\2SPI9KEA4C
    • CfiD = dword:00000005
  • In HKEY_CURRENT_USER\Software\2SPI9KEA4C
    • Cfi3 = dword:01cbe836
  • In HKEY_CURRENT_USER\Software\2SPI9KEA4C
    • CfiE = dword:b43f5ac0
  • In HKEY_CURRENT_USER\Software\2SPI9KEA4C
    • Cku2 = {encrypted data}
  • In HKEY_CURRENT_USER\Software\2SPI9KEA4C
    • CfiK = dword:00000679
  • In HKEY_CURRENT_USER\Software\2SPI9KEA4C
    • Cfi2 = dword:00000001
  • In HKEY_CURRENT_USER\Software\2SPI9KEA4C
    • CfiE3 = dword:00000001
  • In HKEY_CURRENT_USER\Software\2SPI9KEA4C
    • CfiE3 = dword:00000001
  • In HKEY_CURRENT_USER\Software\2SPI9KEA4C
    • Cku9 = {encrypted data}
  • In HKEY_CURRENT_USER\Software\2SPI9KEA4C
    • Cku4 = {encrypted data}

Step 4

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_CURRENT_USER\Software\
    • 2SPI9KEA4C

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. %Windows%\Tasks\{62C40AA6-4406-467a-A5A5-DFDF1B559B7A}.job

Step 6

Scan your computer with your Trend Micro product to delete files detected as TROJ_KRYPTIK.SM7. 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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