sigmahighHunting

Suspicious IIS Module Registration

Detects a suspicious IIS module registration as described in Microsoft threat report on IIS backdoors

MITRE ATT&CK

persistence

Detection Query

selection_parent:
  ParentImage|endswith: \w3wp.exe
selection_cli_1:
  CommandLine|contains: appcmd.exe add module
selection_cli_2:
  CommandLine|contains: " system.enterpriseservices.internal.publish"
  Image|endswith: \powershell.exe
selection_cli_3:
  CommandLine|contains|all:
    - gacutil
    - " /I"
condition: selection_parent and 1 of selection_cli_*

Author

Florian Roth (Nextron Systems), Microsoft (idea)

Created

2022-08-04

Data Sources

windowsProcess Creation Events

Platforms

windows

References

https://www.microsoft.com/security/blog/2022/07/26/malicious-iis-extensions-quietly-open-persistent-backdoors-into-servers/

Tags

attack.persistenceattack.t1505.004

Raw Content

title: Suspicious IIS Module Registration
id: 043c4b8b-3a54-4780-9682-081cb6b8185c
status: test
description: Detects a suspicious IIS module registration as described in Microsoft threat report on IIS backdoors
references:
    - https://www.microsoft.com/security/blog/2022/07/26/malicious-iis-extensions-quietly-open-persistent-backdoors-into-servers/
author: Florian Roth (Nextron Systems), Microsoft (idea)
date: 2022-08-04
modified: 2023-01-23
tags:
    - attack.persistence
    - attack.t1505.004
logsource:
    category: process_creation
    product: windows
detection:
    selection_parent:
        ParentImage|endswith: '\w3wp.exe'
    selection_cli_1:
        CommandLine|contains: 'appcmd.exe add module'
    selection_cli_2:
        CommandLine|contains: ' system.enterpriseservices.internal.publish'
        Image|endswith: '\powershell.exe'
    selection_cli_3:
        CommandLine|contains|all:
            - 'gacutil'
            - ' /I'
    condition: selection_parent and 1 of selection_cli_*
falsepositives:
    - Administrative activity
level: high