Sigma rule: PowerShell Base64 Encoded Invoke Keyword

A detection rule from the SigmaHQ repository, shown as its author published it. Dataset version ref-47f4e12686b8, updated 2023-04-06T00:00:00.000Z.

Rule

Title
PowerShell Base64 Encoded Invoke Keyword
Status
test
Level
high
Author
pH-T (Nextron Systems), Harjot Singh, @cyb3rjy0t
Date
2022-05-20
Modified
2023-04-06
File
rules/windows/process_creation/proc_creation_win_powershell_base64_invoke.yml
Commit
ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects UTF-8 and UTF-16 Base64 encoded powershell 'Invoke-' calls

Log source

product
windows
category
process_creation

Detection

selection_img:
    - Image|endswith:
          - '\powershell.exe'
          - '\pwsh.exe'
    - OriginalFileName:
          - 'PowerShell.EXE'
          - 'pwsh.dll'
selection_cli_enc:
    CommandLine|contains: ' -e'
selection_cli_invoke:
    CommandLine|contains:
        # Invoke-
        # UTF-16LE
        - 'SQBuAHYAbwBrAGUALQ'
        - 'kAbgB2AG8AawBlAC0A'
        - 'JAG4AdgBvAGsAZQAtA'
        # UTF-8
        - 'SW52b2tlL'
        - 'ludm9rZS'
        - 'JbnZva2Ut'
condition: all of selection_*

False positives (as the rule lists them)

  • Unknown

Tags

  • attack.execution
  • attack.stealth
  • attack.t1059.001
  • attack.t1027

MITRE ATT&CK ids this rule names

Related rules

References

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/process_creation/proc_creation_win_powershell_base64_invoke.yml

Sources and licences

  • SigmaHQ

    "PowerShell Base64 Encoded Invoke Keyword" by pH-T (Nextron Systems), Harjot Singh, @cyb3rjy0t (SigmaHQ). Rule: https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/process_creation/proc_creation_win_powershell_base64_invoke.yml.
    Licensed under the Detection Rule License (DRL) 1.1: https://github.com/SigmaHQ/Detection-Rule-License

    Detection Rule License (DRL) 1.1

Cite this page

Dragons Eye Ransomware Tracker, "Sigma rule: PowerShell Base64 Encoded Invoke Keyword",
entity page, dataset version ref-47f4e12686b8, updated 2023-04-06T00:00:00.000Z,
https://ransomware-tracker.com/detections/sigma/6385697e-9f1b-40bd-8817-f4a91f40508e (accessed 2026-11-03).
Underlying source: SigmaHQ rule 6385697e-9f1b-40bd-8817-f4a91f40508e, commit ccbb0369507f796db0b0ae6854c8a2be471b9d84.

Pages change. The dataset version identifies the data, but no archive of old versions is kept, so this citation cannot be replayed later.