Sigma Rule Library

Script Interpreter Execution From Suspicious Folder

Detects suspicious script execution from suspicious directories or folders accessible by environment variables that may indicate malware activity. Script interpreters (cscript, wscript, mshta, powershell) executing from folders like Temp, Public, or user profile directories may suggest attempts to evade detection or execute malicious scripts.

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Detection logic

selection_proc_image

Image|endswith:
  - \cscript.exe
  - \mshta.exe
  - \wscript.exe

selection_proc_flags

CommandLine|contains:
  - " -ep bypass "
  - " -ExecutionPolicy bypass "
  - " -w hidden "
  - "/e:javascript "
  - "/e:Jscript "
  - "/e:vbscript "

selection_proc_original

OriginalFileName:
  - cscript.exe
  - mshta.exe
  - wscript.exe

selection_folders_1

CommandLine|contains:
  - :\Perflogs\
  - :\Users\Public\
  - \%Public%
  - \AppData\Local\Temp
  - \AppData\Roaming\Temp
  - \Temporary Internet
  - \Windows\Temp
  - \Start Menu\Programs\Startup\
  - "%TEMP%"
  - "%TMP%"
  - "%LocalAppData%\\Temp"

selection_folders_2

- CommandLine|contains|all:
    - :\Users\
    - \Favorites\
- CommandLine|contains|all:
    - :\Users\
    - \Favourites\
- CommandLine|contains|all:
    - :\Users\
    - \Contacts\
- CommandLine|contains|all:
    - :\Users\
    - \Documents\
- CommandLine|contains|all:
    - :\Users\
    - \Music\
- CommandLine|contains|all:
    - :\Users\
    - \Pictures\
- CommandLine|contains|all:
    - :\Users\
    - \Videos\

filter_optional_chocolatey_installer

ParentImage:
  - C:\Windows\System32\Msiexec.exe
  - C:\Windows\SysWOW64\Msiexec.exe
Image|endswith: \powershell.exe
CommandLine|contains|all:
  - -NoProfile -ExecutionPolicy Bypass -Command
  - AppData\Local\Temp\
  - Install-Chocolatey.ps1

Condition

1 of selection_proc_* and 1 of selection_folders_* and not 1 of filter_optional_*

Raw YAML

title: Script Interpreter Execution From Suspicious Folder
id: 1228c958-e64e-4e71-92ad-7d429f4138ba
status: test
description: |
    Detects suspicious script execution from suspicious directories or folders accessible by environment variables that may indicate malware activity.
    Script interpreters (cscript, wscript, mshta, powershell) executing from folders like Temp, Public, or user profile directories may suggest attempts to evade detection or execute malicious scripts.
references:
    - https://www.virustotal.com/gui/file/91ba814a86ddedc7a9d546e26f912c541205b47a853d227756ab1334ade92c3f
    - https://symantec-enterprise-blogs.security.com/blogs/threat-intelligence/shuckworm-russia-ukraine-military
    - https://learn.microsoft.com/en-us/windows/win32/shell/csidl
author: Florian Roth (Nextron Systems), Nasreddine Bencherchali (Nextron Systems)
date: 2022-02-08
modified: 2026-02-17
tags:
    - attack.execution
    - attack.t1059
logsource:
    category: process_creation
    product: windows
detection:
    selection_proc_image:
        Image|endswith:
            - '\cscript.exe'
            - '\mshta.exe'
            - '\wscript.exe'
    selection_proc_flags:
        CommandLine|contains:
            - ' -ep bypass '
            - ' -ExecutionPolicy bypass '
            - ' -w hidden '
            - '/e:javascript '
            - '/e:Jscript '
            - '/e:vbscript '
    selection_proc_original:
        OriginalFileName:
            - 'cscript.exe'
            - 'mshta.exe'
            - 'wscript.exe'
    selection_folders_1:
        CommandLine|contains:
            - ':\Perflogs\'
            - ':\Users\Public\'
            - '\%Public%'
            - '\AppData\Local\Temp'
            - '\AppData\Roaming\Temp'
            - '\Temporary Internet'
            - '\Windows\Temp'
            - '\Start Menu\Programs\Startup\'
            - '%TEMP%'
            - '%TMP%'
            - '%LocalAppData%\Temp'
    selection_folders_2:
        - CommandLine|contains|all:
              - ':\Users\'
              - '\Favorites\'
        - CommandLine|contains|all:
              - ':\Users\'
              - '\Favourites\'
        - CommandLine|contains|all:
              - ':\Users\'
              - '\Contacts\'
        - CommandLine|contains|all:
              - ':\Users\'
              - '\Documents\'
        - CommandLine|contains|all:
              - ':\Users\'
              - '\Music\'
        - CommandLine|contains|all:
              - ':\Users\'
              - '\Pictures\'
        - CommandLine|contains|all:
              - ':\Users\'
              - '\Videos\'
    filter_optional_chocolatey_installer:
        ParentImage:
            - 'C:\Windows\System32\Msiexec.exe'
            - 'C:\Windows\SysWOW64\Msiexec.exe'
        Image|endswith: '\powershell.exe'
        CommandLine|contains|all:
            - '-NoProfile -ExecutionPolicy Bypass -Command'
            - 'AppData\Local\Temp\'
            - 'Install-Chocolatey.ps1'
    condition: 1 of selection_proc_* and 1 of selection_folders_* and not 1 of filter_optional_*
falsepositives:
    - Various legitimate software have been observed to use similar techniques for installation or update purposes;thus, it is recommended to review and tune filters for your environment to reduce false positives before deploying to production.
level: high

False positives

  • Various legitimate software have been observed to use similar techniques for installation or update purposes;thus, it is recommended to review and tune filters for your environment to reduce false positives before deploying to production.

References

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