name: Suspicious MSHTA Activity
id: 2b1800dd-92f9-47dd-a981-fdf13w1q5d55
version: 2
date: '2021-01-20'
author: Bhavin Patel, Michael Haag, Splunk
type: batch
description: Monitor and detect techniques used by attackers who leverage the mshta.exe
  process to execute malicious code.
narrative: 'One common adversary tactic is to bypass application control solutions
  via the mshta.exe process, which loads Microsoft HTML applications (mshtml.dll)
  with the .hta suffix. In these cases, attackers use the trusted Windows utility
  to proxy execution of malicious files, whether an .hta application, javascript,
  or VBScript.\

  The searches in this story help you detect and investigate suspicious activity that
  may indicate that an attacker is leveraging mshta.exe to execute malicious code.\

  Triage\ 
  
  Validate execution \ 
  
  1. Determine if MSHTA.exe executed. Validate the OriginalFileName
  of MSHTA.exe and further PE metadata. If executed outside of c:\windows\system32
  or c:\windows\syswow64, it should be highly suspect.\

  1. Determine if script code was executed with MSHTA.\

  Situational Awareness\ 
  
  The objective of this step is meant to identify suspicious
  behavioral indicators related to executed of Script code by MSHTA.exe.\

  1. Parent process. Is the parent process a known LOLBin? Is the parent process an
  Office Application?\

  1. Module loads. Are the known MSHTA.exe modules being loaded by a non-standard
  application? Is MSHTA loading any suspicious .DLLs?\

  1. Network connections. Any network connections? Review the reputation of the remote
  IP or domain.\

  Retrieval of script code\ 
  
  The objective of this step is to confirm the executed
  script code is benign or malicious.'
references:
- https://redcanary.com/blog/introducing-atomictestharnesses/
- https://redcanary.com/blog/windows-registry-attacks-threat-detection/
- https://attack.mitre.org/techniques/T1218/005/
- https://medium.com/@mbromileyDFIR/malware-monday-aebb456356c5
tags:
  analytics_story: Suspicious MSHTA Activity
  category:
  - Adversary Tactics
  usecase: Advanced Threat Detection
  product:
  - Splunk Enterprise
  - Splunk Enterprise Security
  - Splunk Cloud
