IIS Native-Code Module Command Line Installation — Sigma Rule

Rule metadata and linked tags

Author: Florian Roth (Nextron Systems). Source status: test; severity: medium. Source dates: 2019-12-11 / 2024-03-13.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 15537dbd52d80be94495376345574208705cbba8a4e2e1b2fad6eba881040160

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: IIS Native-Code Module Command Line Installation
id: 9465ddf4-f9e4-4ebd-8d98-702df3a93239
status: test
description: Detects suspicious IIS native-code module installations via command line
references:
    - https://researchcenter.paloaltonetworks.com/2018/01/unit42-oilrig-uses-rgdoor-iis-backdoor-targets-middle-east/
    - https://www.microsoft.com/security/blog/2022/07/26/malicious-iis-extensions-quietly-open-persistent-backdoors-into-servers/
author: Florian Roth (Nextron Systems)
date: 2019-12-11
modified: 2024-03-13
tags:
    - attack.persistence
    - attack.t1505.003
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        - Image|endswith: '\appcmd.exe'
        - OriginalFileName: 'appcmd.exe'
    selection_cli:
        CommandLine|contains|all:
            - 'install'
            - 'module'
        CommandLine|contains|windash: '-name:'
    filter_iis_setup:
        ParentImage: 'C:\Windows\System32\inetsrv\iissetup.exe'
    condition: all of selection_* and not 1 of filter_*
falsepositives:
    - Unknown as it may vary from organisation to organisation how admins use to install IIS modules
level: medium

Original YAML and metadata in JSON

False positives

• Unknown as it may vary from organisation to organisation how admins use to install IIS modules

Source references

• https://researchcenter.paloaltonetworks.com/2018/01/unit42-oilrig-uses-rgdoor-iis-backdoor-targets-middle-east/
• https://www.microsoft.com/security/blog/2022/07/26/malicious-iis-extensions-quietly-open-persistent-backdoors-into-servers/