VMGuestLib DLL Sideload — Sigma Rule

Rule metadata and linked tags

Author: Nasreddine Bencherchali (Nextron Systems). Source status: test; severity: medium. Source dates: 2022-12-01 / not supplied.

{
  "category": "image_load",
  "product": "windows"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: b1e06957d7772c59c365eea1bff58284f3b7026b76933660d25dc883cedda028

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: VMGuestLib DLL Sideload
id: 70e8e9b4-6a93-4cb7-8cde-da69502e7aff
status: test
description: Detects DLL sideloading of VMGuestLib.dll by the WmiApSrv service.
references:
    - https://decoded.avast.io/martinchlumecky/png-steganography/
author: Nasreddine Bencherchali (Nextron Systems)
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

Original YAML and metadata in JSON

False positives

• FP could occur if the legitimate version of vmGuestLib already exists on the system

Source references

• https://decoded.avast.io/martinchlumecky/png-steganography/