MSHTA Execution with Suspicious File Extensions

Title: MSHTA Execution with Suspicious File Extensions
Status: test
Description:Detects execution of mshta.exe with file types that looks like they do not typically represent HTA (HTML Application) content, such as .png, .jpg, .zip, .pdf, and others, which are often polyglots. MSHTA is a legitimate Windows utility for executing HTML Applications containing VBScript or JScript. Threat actors often abuse this lolbin utility to download and execute malicious scripts disguised as benign files or hosted under misleading extensions to evade detection.
References:
  -http://blog.sevagas.com/?Hacking-around-HTA-files
  -https://0x00sec.org/t/clientside-exploitation-in-2018-how-pentesting-has-changed/7356
  -https://learn.microsoft.com/en-us/previous-versions/dotnet/framework/data/xml/xslt/xslt-stylesheet-scripting-using-msxsl-script
  -https://medium.com/tsscyber/pentesting-and-hta-bypassing-powershell-constrained-language-mode-53a42856c997
  -https://twitter.com/mattifestation/status/1326228491302563846
  -https://www.virustotal.com/gui/file/c1f27d9795a2eba630db8a043580a0761798f06370fb1317067805f8a845b00c
Author: Diego Perez (@darkquassar), Markus Neis, Swisscom (Improve Rule), Swachchhanda Shrawan Poudel (Nextron Systems)
Date: 2019-02-22
modified:2025-05-12
Tags:

• -'attack.stealth'
• -'attack.t1140'
• -'attack.t1218.005'
• -'attack.execution'
• -'attack.t1059.007'
• -'cve.2020-1599'

Logsource:

• category: process_creation
• product: windows

Detection:
  selection_img:
Image|endswith:'\mshta.exe' OriginalFileName:'mshta.exe'   selection_cli:
    CommandLine|contains:
      -'.7z'
      -'.avi'
      -'.bat'
      -'.bmp'
      -'.conf'
      -'.csv'
      -'.dll'
      -'.doc'
      -'.gif'
      -'.gz'
      -'.ini'
      -'.jpe'
      -'.jpg'
      -'.json'
      -'.lnk'
      -'.log'
      -'.mkv'
      -'.mp3'
      -'.mp4'
      -'.pdf'
      -'.png'
      -'.ppt'
      -'.rar'
      -'.rtf'
      -'.svg'
      -'.tar'
      -'.tmp'
      -'.txt'
      -'.xls'
      -'.xml'
      -'.yaml'
      -'.yml'
      -'.zip'
      -'vbscript'

  condition:all of selection_*
Falsepositives:
  -False positives depend on scripts and administrative tools used in the monitored environment
Level: high