JS_KRYPTIK.KA

December 13, 2016
 Analysis by: Cris Nowell Pantanilla
 PLATFORM:

Windows

 OVERALL RISK RATING:
 REPORTED INFECTION:

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

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.

  TECHNICAL DETAILS

File Size:

20,231 bytes

File Type:

JS

Memory Resident:

No

Initial Samples Received Date:

12 Dec 2016

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.

Other System Modifications

This Trojan adds the following registry entries:

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\RunOnce
Lofih = "%WINDOWS%\SysWOW64\wscript.exe /E:vbscript /B %System Root%\Users\E5250716\AppData\Roaming\Cekete"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\RunOnce
Lofih = "%WINDOWS%\SysWOW64\wscript.exe /E:vbscript /B %System Root%\Users\E5250716\AppData\Roaming\Cekete"

Other Details

This Trojan does the following:

  • It executes the following file. As a result, behavior of the said file is exhibited on the affected system:
    • %System Root%\Users\E5250716\AppData\Local\UpdateTask\updatetaskupdate.exe

(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.)

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

12.956.06

FIRST VSAPI PATTERN DATE:

12 Dec 2016

VSAPI OPR PATTERN File:

12.957.00

VSAPI OPR PATTERN Date:

13 Dec 2016

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

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\RunOnce
    • Lofih = "%WINDOWS%\SysWOW64\wscript.exe /E:vbscript /B %System Root%\Users\E5250716\AppData\Roaming\Cekete"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\RunOnce
    • Lofih = "%WINDOWS%\SysWOW64\wscript.exe /E:vbscript /B %System Root%\Users\E5250716\AppData\Roaming\Cekete"

Step 3

Scan your computer with your Trend Micro product to delete files detected as JS_KRYPTIK.KA. 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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