Windows ImageLoad of DLL from spoolsv.exe spool drivers subfolders
Flags spoolsv.exe DLL loads originating from Print Spooler x64\3/x64\4 driver folders on Windows.
- Product
- windows
- Category
- image_load
- Author
- FPT.EagleEye, Thomas Patzke (improvements) (SigmaHQ), DRL 1.1
- Published
- 2021-06-29
- Updated
- 2026-07-31
ATT&CK techniques
Execution → Defense EvasionRecon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact
What it detects
This rule flags DLL loads where the initiating image is spoolsv.exe and the loaded module path matches specific spool driver x64 subfolders. Such behavior can indicate print spooler abuse or persistence attempts that load additional code through the spooler service. It relies on Windows image load telemetry that includes both the initiating Image and the ImageLoaded path for .dll modules.
Reporting behind it
- web.archive.orghttps://web.archive.org/web/20210629055600/https://github.com/hhlxf/PrintNightmare/
- github.comhttps://github.com/ly4k/SpoolFool
- github.comhttps://github.com/SigmaHQ/sigma/blob/master/rules-emerging-threats/2021/Exploits/CVE-2021-1675/image_load_exploit_cve_2021_1675_spoolsv_dll_load.yml
Changelog
v5- v5Candidate ingested via manual entry.2026-07-31
- v4Candidate ingested via manual entry.2026-07-31
- v3Candidate ingested via manual entry.2026-07-31
- v2Candidate ingested via manual entry.2026-07-31
- v1No changelog recorded for this version.2026-07-30
Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.
title: Windows ImageLoad of DLL from spoolsv.exe spool drivers subfolders
id: fc01012f-a4a4-4e18-a25e-8b30ee9320c3
status: test
description: This rule flags DLL loads where the initiating image is spoolsv.exe and the loaded module path matches specific spool driver x64 subfolders. Such behavior can indicate print spooler abuse or persistence attempts that load additional code through the spooler service. It relies on Windows image load telemetry that includes both the initiating Image and the ImageLoaded path for .dll modules.
references:
- https://web.archive.org/web/20210629055600/https://github.com/hhlxf/PrintNightmare/
- https://github.com/ly4k/SpoolFool
- https://github.com/SigmaHQ/sigma/blob/master/rules-emerging-threats/2021/Exploits/CVE-2021-1675/image_load_exploit_cve_2021_1675_spoolsv_dll_load.yml
author: FPT.EagleEye, Thomas Patzke (improvements), Huntrule Team
date: 2021-06-29
modified: 2022-06-02
tags:
- attack.persistence
- attack.privilege-escalation
- attack.execution
- attack.stealth
- attack.t1574
- cve.2021-1675
- cve.2021-34527
- detection.emerging-threats
logsource:
category: image_load
product: windows
detection:
selection:
Image|endswith: \spoolsv.exe
ImageLoaded|contains:
- \Windows\System32\spool\drivers\x64\3\
- \Windows\System32\spool\drivers\x64\4\
ImageLoaded|endswith: .dll
condition: selection
falsepositives:
- Loading of legitimate driver
level: informational
license: DRL-1.1
related:
- id: 02fb90de-c321-4e63-a6b9-25f4b03dfd14
type: derived