Sigma rule: PowerShell Base64 Encoded Reflective Assembly Load

A detection rule from the SigmaHQ repository, shown as its author published it. Dataset version ref-3252b070d6a8, updated 2023-01-30T00:00:00.000Z.

Rule

Title
PowerShell Base64 Encoded Reflective Assembly Load
Status
test
Level
high
Author
Christian Burkard (Nextron Systems), pH-T (Nextron Systems)
Date
2022-03-01
Modified
2023-01-30
File
rules/windows/process_creation/proc_creation_win_powershell_base64_reflection_assembly_load.yml
Commit
ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects base64 encoded .NET reflective loading of Assembly

Log source

product
windows
category
process_creation

Detection

selection:
    CommandLine|contains:
        # [Reflection.Assembly]::Load(
        - 'WwBSAGUAZgBsAGUAYwB0AGkAbwBuAC4AQQBzAHMAZQBtAGIAbAB5AF0AOgA6AEwAbwBhAGQAKA'
        - 'sAUgBlAGYAbABlAGMAdABpAG8AbgAuAEEAcwBzAGUAbQBiAGwAeQBdADoAOgBMAG8AYQBkACgA'
        - 'bAFIAZQBmAGwAZQBjAHQAaQBvAG4ALgBBAHMAcwBlAG0AYgBsAHkAXQA6ADoATABvAGEAZAAoA'
        # [reflection.assembly]::("Load")
        - 'AFsAcgBlAGYAbABlAGMAdABpAG8AbgAuAGEAcwBzAGUAbQBiAGwAeQBdADoAOgAoACIATABvAGEAZAAiAC'
        - 'BbAHIAZQBmAGwAZQBjAHQAaQBvAG4ALgBhAHMAcwBlAG0AYgBsAHkAXQA6ADoAKAAiAEwAbwBhAGQAIgAp'
        - 'AWwByAGUAZgBsAGUAYwB0AGkAbwBuAC4AYQBzAHMAZQBtAGIAbAB5AF0AOgA6ACgAIgBMAG8AYQBkACIAK'
        # [Reflection.Assembly]::("Load")
        - 'WwBSAGUAZgBsAGUAYwB0AGkAbwBuAC4AQQBzAHMAZQBtAGIAbAB5AF0AOgA6ACgAIgBMAG8AYQBkACIAKQ'
        - 'sAUgBlAGYAbABlAGMAdABpAG8AbgAuAEEAcwBzAGUAbQBiAGwAeQBdADoAOgAoACIATABvAGEAZAAiACkA'
        - 'bAFIAZQBmAGwAZQBjAHQAaQBvAG4ALgBBAHMAcwBlAG0AYgBsAHkAXQA6ADoAKAAiAEwAbwBhAGQAIgApA'
        # [reflection.assembly]::Load(
        - 'WwByAGUAZgBsAGUAYwB0AGkAbwBuAC4AYQBzAHMAZQBtAGIAbAB5AF0AOgA6AEwAbwBhAGQAKA'
        - 'sAcgBlAGYAbABlAGMAdABpAG8AbgAuAGEAcwBzAGUAbQBiAGwAeQBdADoAOgBMAG8AYQBkACgA'
        - 'bAHIAZQBmAGwAZQBjAHQAaQBvAG4ALgBhAHMAcwBlAG0AYgBsAHkAXQA6ADoATABvAGEAZAAoA'
condition: selection

False positives (as the rule lists them)

  • Unlikely

Tags

  • attack.execution
  • attack.stealth
  • attack.t1059.001
  • attack.t1027
  • attack.t1620

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_reflection_assembly_load.yml

Sources and licences

  • SigmaHQ

    "PowerShell Base64 Encoded Reflective Assembly Load" by Christian Burkard (Nextron Systems), pH-T (Nextron Systems) (SigmaHQ). Rule: https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/process_creation/proc_creation_win_powershell_base64_reflection_assembly_load.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 Reflective Assembly Load",
entity page, dataset version ref-3252b070d6a8, updated 2023-01-30T00:00:00.000Z,
https://ransomware-tracker.com/detections/sigma/62b7ccc9-23b4-471e-aa15-6da3663c4d59 (accessed 2026-11-03).
Underlying source: SigmaHQ rule 62b7ccc9-23b4-471e-aa15-6da3663c4d59, 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.