Detection rules › Sigma

Script Interpreter Execution From Suspicious Folder

Status
test
Severity
high
Log source
category process_creation, product windows
Author
Florian Roth (Nextron Systems), Nasreddine Bencherchali (Nextron Systems)
Source
github.com/SigmaHQ/sigma

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.

Known 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.

MITRE ATT&CK coverage

Telemetry coverage

ProviderRecord / event type
SysmonEvent ID 1: Process creation

Rule body

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

Stages and Predicates

Stage 0: condition

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

Stage 1: selection_proc_image

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

Stage 2: selection_proc_flags

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

Stage 3: selection_proc_original

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

Stage 4: selection_folders_1

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'

Stage 5: selection_folders_2

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\'

Stage 6: not filter_optional_chocolatey_installer

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'

Exclusions

The rule actively suppresses these predicates.

Indicators

These rows show field, operator, and value matches.

FieldKindValuesSearch
CommandLinematch
  • -ExecutionPolicy bypass
  • -ep bypass
  • -w hidden corpus 5 (sigma 5)
  • %LocalAppData%\Temp corpus 2 (sigma 2)
  • %TEMP% corpus 16 (sigma 13, chronicle 2, kusto 1)
  • %TMP% corpus 15 (sigma 13, chronicle 2)
  • /e:Jscript
  • /e:javascript
  • /e:vbscript
  • :\Perflogs\ corpus 11 (sigma 11)
  • :\Users\ corpus 6 (sigma 6)
  • :\Users\Public\ corpus 20 (sigma 18, elastic 2)
  • \%Public%
  • \AppData\Local\Temp corpus 8 (sigma 8)
  • \AppData\Roaming\Temp corpus 2 (sigma 2)
  • \Contacts\ corpus 7 (sigma 7)
  • \Documents\ corpus 2 (sigma 2)
  • \Favorites\ corpus 7 (sigma 7)
  • \Favourites\ corpus 7 (sigma 7)
  • \Music\ corpus 4 (sigma 4)
  • \Pictures\ corpus 5 (sigma 5)
  • \Start Menu\Programs\Startup\ corpus 3 (sigma 3)
  • \Temporary Internet corpus 7 (sigma 7)
  • \Videos\ corpus 4 (sigma 4)
  • \Windows\Temp corpus 3 (sigma 3)
field:"CommandLine" kind:match
Imageends_with
  • \cscript.exe corpus 72 (sigma 72)
  • \mshta.exe corpus 66 (sigma 66)
  • \wscript.exe corpus 74 (sigma 74)
field:"Image" kind:ends_with
OriginalFileNameeq
  • cscript.exe corpus 32 (sigma 17, elastic 15)
  • mshta.exe corpus 40 (elastic 21, sigma 13, splunk 6)
  • wscript.exe corpus 38 (elastic 21, sigma 17)
field:"OriginalFileName" kind:eq