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Worm:ACAD/Kenilfe.A

Classification

Category: Malware

Type: Worm

Platform: ACAD

Aliases: Kenife, Kenilfe, Kenilfe.A, Worm.Acad.Kenilfe.A, AutoCAD.Kenilfe, AL/Kenilfe

Summary


Kenilfe is a malicious AutoCAD program that propagates via removable drives. It also attempts to download Visual Basic Scripts from remote servers, if certain conditions are met.

Removal


Automatic action

Based on the settings of your F-Secure security product, it will either automatically delete, quarantine or rename the detected program or file, or ask you for a desired action.

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Technical Details


Installation

During installation, the malware creates the following registry entries:

  • HKEY_CURRENT_USER\Software\KenFiles\settings TMN = %Random Name% or "Temp" TMNL = %Random Name% or "TMNL" SHXN = %Random Name% or "isoshfr" CXBB = 102 GXBZ = 103 pth0 = %IP Address of updatebd.8800.org% (or "221223921023103" if cannot ping the host) pth3 = %Current Date% pth4 = %Current Date% pth5 = %Current Date% basepth = %User Support Folder% fontpth = %AutoCAD Fonts Folder%

It then creates copies of itself in the following locations:

  • %Folder of Current Drawing%\acad.fas
  • %User Support Folder%\acad.fas
  • %AutoCAD Fonts Folder%\%SHXN%.shx

Where%SHXN% is the same as the SHXN value found in the registry entry (above).

It also creates the following files:

  • %Windows Folder%\DivX.fin - possibly some sort of a infection marker
  • %Windows Folder%\system32\%TMN%.cmd - contains commands that will create copies of the malware (same as those mentioned earlier)

Where%TMN% is also the same as the TMN value found in the registry entry.

It enables the Windows Scripting Host by creating the following registry entry:

  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Script Host\Settings Enabled = 1

Then deletes the registry key:

  • "HKEY_CURRENT_USER\Software\FileKen\settings"

It also deletes the following files:

  • isohztxt.shx
  • acad.fas1
  • logo.gif
  • isomianyi.shx
Payload

Once installed, Kenilfe downloads and executes Visual Basic Scripts based on the following conditons:

  • https://www.cadgs.com/[...]/gxcx.[...] - if the 3rd octect of the IP address of updatebd.8800.org > 102
  • https://www.cadgs.com/[...]/gxmz.[...] - if the 4th octect of the IP address of updatebd.8800.org > 103

Example: if the IP address of updatebd.8800.org is 221.239.103.104, both Visual Basic Scripts will be downloaded and executed.

These conditions are specified in the CXBB and GXBZ registry, respectively.

Propagation

The malware enumerates all folders in all removable drives. If it finds the file acad.fas, it replaces the file with a copy of

  • %AutoCAD Fonts Folder%\isomianyi.shx.

Alternatively, if the folder contains a drawing (.dwg) file, it will create the file acad.fas (which is really a copy of isomianyi.shx).

It then creates a file named pagefile in the same drive location, to mark that it is done infected the drive.

During the enumeration process, the malware also renames the following files to append a "_bak" in their filenames:

  • acad.lsp
  • acad.sys
  • acad.vlx
  • acadapp.lsp
  • acadappp.lsp
  • acadapq.lsp
  • acadiso.lsp
  • acadsmu.fas
  • dwgrun.bat
  • isohztxt.shx
  • lcm.fas
  • winfas.ini

Description Created: 2009-07-08 11:59:43.0

Description Last Modified: 2015-01-19 09:50