Detection rules › Sigma
Amsi.DLL Loaded Via LOLBIN Process
Detects loading of "Amsi.dll" by a living of the land process. This could be an indication of a "PowerShell without PowerShell" attack
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Defense Impairment | No specific technique |
Telemetry coverage
| Provider | Record / event type |
|---|---|
| Sysmon | Event ID 7: Image loaded |
Rule body
title: Amsi.DLL Loaded Via LOLBIN Process
id: 6ec86d9e-912e-4726-91a2-209359b999b9
status: test
description: Detects loading of "Amsi.dll" by a living of the land process. This could be an indication of a "PowerShell without PowerShell" attack
references:
- Internal Research
- https://www.paloaltonetworks.com/blog/security-operations/stopping-powershell-without-powershell/
author: Nasreddine Bencherchali (Nextron Systems)
date: 2023-06-01
modified: 2025-10-07
tags:
- attack.defense-impairment
logsource:
category: image_load
product: windows
detection:
selection:
ImageLoaded|endswith: '\amsi.dll'
Image|endswith:
# TODO: Add more interesting processes
- '\ExtExport.exe'
- '\odbcconf.exe'
# - '\regsvr32.exe' # legitimately calls amsi.dll
- '\rundll32.exe'
condition: selection
falsepositives:
- Unknown
level: medium
Stages and Predicates
Stage 0: condition
selectionStage 1: selection
selection:
ImageLoaded|endswith: '\amsi.dll'
Image|endswith:
- '\ExtExport.exe'
- '\odbcconf.exe'
- '\rundll32.exe'
Indicators
These rows show field, operator, and value matches.
| Field | Kind | Values | Search |
|---|---|---|---|
Image | ends_with |
| field:"Image" kind:ends_with |
ImageLoaded | ends_with |
| field:"ImageLoaded" kind:ends_with value:"\amsi.dll" |