Windows: DllHost.exe creates a System32 DLL for UAC bypass via IDiagnosticProfileUAC

Alerts when dllhost.exe creates a System32 .dll consistent with IDiagnosticProfileUAC UAC bypass behavior.

FreeReviewedSigma · High · v2

Product: windows
Category: file_event
Author: Nasreddine Bencherchali (Nextron Systems) (SigmaHQ), DRL 1.1
Published: 2022-07-03
Updated: 2026-07-31

ATT&CK techniques

Priv Esc → Defense Evasion

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
- T1548.002Bypass User Account Control
Defense Evasion
- T1548.002Bypass User Account Control
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule identifies a suspicious file creation where DllHost.exe writes a DLL into the C:\Windows\System32\ directory. Creating a System32 DLL from a user-space process is a common step in UAC bypass workflows because it can enable elevated execution paths. The detection relies on file event telemetry that provides the initiating process image and the target file path and extension.

Reporting behind it

Related detections9 linkedT1548.002 — drag to rearrange

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Suspicious dllhost.exe Spawned with CLSID and Anomalous Parent (via process_creation)

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Suspicious Mock Trusted Directory with Trailing Space (via process_creation)

Windows: DllHost.exe creates a System32 DLL for UAC bypass via IDiagnosticProfileUAC

Pivot detection · T1548.002 · 9 related

Changelog

v2
Candidate ingested via manual entry.2026-07-31
v1
No 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.

windows-uac-bypass-via-idiagnosticprofileuac-dllhost-exe-writing-dll-in-system32-48ea844d

title: "Windows: DllHost.exe creates a System32 DLL for UAC bypass via IDiagnosticProfileUAC"
id: ba4936ac-9c73-4593-bc7f-f06c00a13486
status: test
description: This rule identifies a suspicious file creation where DllHost.exe writes a DLL into the C:\Windows\System32\ directory. Creating a System32 DLL from a user-space process is a common step in UAC bypass workflows because it can enable elevated execution paths. The detection relies on file event telemetry that provides the initiating process image and the target file path and extension.
references:
  - https://github.com/Wh04m1001/IDiagnosticProfileUAC
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/file/file_event/file_event_win_uac_bypass_idiagnostic_profile.yml
author: Nasreddine Bencherchali (Nextron Systems), Huntrule Team
date: 2022-07-03
tags:
  - attack.execution
  - attack.privilege-escalation
  - attack.t1548.002
logsource:
  product: windows
  category: file_event
detection:
  selection:
    Image|endswith: \DllHost.exe
    TargetFilename|startswith: C:\Windows\System32\
    TargetFilename|endswith: .dll
  condition: selection
falsepositives:
  - Unknown
level: high
license: DRL-1.1
related:
  - id: 48ea844d-19b1-4642-944e-fe39c2cc1fec
    type: derived

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