Sigma rule: Assembly Loading Via CL_LoadAssembly.ps1

Rule

Title

Assembly Loading Via CL_LoadAssembly.ps1

Status

test

Level

medium

Author

frack113, Nasreddine Bencherchali (Nextron Systems)

Date

2022-05-21

Modified

2023-08-17

File

rules/windows/process_creation/proc_creation_win_powershell_cl_loadassembly.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects calls to "LoadAssemblyFromPath" or "LoadAssemblyFromNS" that are part of the "CL_LoadAssembly.ps1" script. This can be abused to load different assemblies and bypass App locker controls.

Log source

product

windows

category

process_creation

Detection

selection:
    # Note: As this function is usually called from within powershell, classical process creation even would not catch it. This will only catch inline calls via "-Command" or "-ScriptBlock" flags for example.
    CommandLine|contains:
        - 'LoadAssemblyFromPath '
        - 'LoadAssemblyFromNS '
condition: selection

False positives (as the rule lists them)

• Unknown

Tags

• attack.stealth
• attack.t1216

MITRE ATT&CK ids this rule names

• T1216

References

• https://bohops.com/2018/01/07/executing-commands-and-bypassing-applocker-with-powershell-diagnostic-scripts/
• https://lolbas-project.github.io/lolbas/Scripts/CL_LoadAssembly/

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_cl_loadassembly.yml