Windows DLL Sideloading: WmiApSrv Loads VMGuestLib.dll

Flags WmiApSrv.exe loading VMGuestLib.dll from VMware Tools vmStatsProvider on Windows.

FreeReviewedSigma · Medium · v2

Product: windows
Category: image_load
Author: Nasreddine Bencherchali (Nextron Systems) (SigmaHQ), DRL 1.1
Published: 2022-12-01
Updated: 2026-07-31

ATT&CK techniques

Execution → Defense Evasion

Recon
Resource Dev
Initial Access
Execution
- T1574.001DLL
Persistence
- T1574.001DLL
Priv Esc
- T1574.001DLL
Defense Evasion
- T1574.001DLL
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule identifies DLL sideloading behavior where WmiApSrv.exe loads vmGuestLib.dll when it appears in the VMware Tools win32 vmStatsProvider path. Attackers may abuse DLL search order to execute or load malicious code under a legitimate Windows process, aiding persistence, privilege escalation, and stealth. The detection relies on image load telemetry that includes the loaded DLL path and the loading executable path, and it excludes cases where the load is marked as signed.

Reporting behind it

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Windows DLL Sideloading: WmiApSrv Loads VMGuestLib.dll

Pivot detection · T1574.001 · 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-vmguestlib-dll-sideloading-via-wmiapsrv-imageload-70e8e9b4

title: "Windows DLL Sideloading: WmiApSrv Loads VMGuestLib.dll"
id: ae66ab4d-8608-415e-88d9-72b3a9b4044d
status: test
description: This rule identifies DLL sideloading behavior where WmiApSrv.exe loads vmGuestLib.dll when it appears in the VMware Tools win32 vmStatsProvider path. Attackers may abuse DLL search order to execute or load malicious code under a legitimate Windows process, aiding persistence, privilege escalation, and stealth. The detection relies on image load telemetry that includes the loaded DLL path and the loading executable path, and it excludes cases where the load is marked as signed.
references:
  - https://decoded.avast.io/martinchlumecky/png-steganography/
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/image_load/image_load_side_load_vmguestlib.yml
author: Nasreddine Bencherchali (Nextron Systems), Huntrule Team
date: 2022-12-01
tags:
  - attack.persistence
  - attack.privilege-escalation
  - attack.execution
  - attack.stealth
  - attack.t1574.001
logsource:
  category: image_load
  product: windows
detection:
  selection:
    ImageLoaded|contains|all:
      - \VMware\VMware Tools\vmStatsProvider\win32
      - \vmGuestLib.dll
    Image|endswith: \Windows\System32\wbem\WmiApSrv.exe
  filter:
    Signed: "true"
  condition: selection and not filter
falsepositives:
  - FP could occur if the legitimate version of vmGuestLib already exists on the system
level: medium
license: DRL-1.1
related:
  - id: 70e8e9b4-6a93-4cb7-8cde-da69502e7aff
    type: derived

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