DllUnregisterServer Function Call Via Msiexec.EXE — Sigma Rule

Rule metadata and linked tags

Author: frack113. Source status: test; severity: medium. Source dates: 2022-04-24 / 2024-03-13.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 4385c2b84a214ea845f0f0e0a9a0df8ba32de4db6369683c3dae3c49c3092533

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: DllUnregisterServer Function Call Via Msiexec.EXE
id: 84f52741-8834-4a8c-a413-2eb2269aa6c8
status: test
description: Detects MsiExec loading a DLL and calling its DllUnregisterServer function
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1218.007/T1218.007.md
    - https://lolbas-project.github.io/lolbas/Binaries/Msiexec/
    - https://twitter.com/_st0pp3r_/status/1583914515996897281
author: frack113
date: 2022-04-24
modified: 2024-03-13
tags:
    - attack.stealth
    - attack.t1218.007
logsource:
    product: windows
    category: process_creation
detection:
    selection_img:
        - Image|endswith: '\msiexec.exe'
        - OriginalFileName: '\msiexec.exe'
    selection_flag:
        CommandLine|contains|windash: ' -z '
    selection_dll:
        CommandLine|contains: '.dll'
    condition: all of selection_*
falsepositives:
    - Unknown
level: medium

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1218.007/T1218.007.md
• https://lolbas-project.github.io/lolbas/Binaries/Msiexec/
• https://twitter.com/_st0pp3r_/status/1583914515996897281