Sigma rule: New Module Module Added To IIS Server

Rule

Title

New Module Module Added To IIS Server

Status

test

Level

medium

Author

frack113

Date

2024-10-06

File

rules/windows/builtin/iis-configuration/win_iis_module_added.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects the addition of a new module to an IIS server.

Log source

product

windows

service

iis-configuration

Detection

selection:
    EventID: 29
    Configuration|contains: '/system.webServer/modules/add'
filter_main_builtin:
    NewValue:
        - 'AnonymousAuthenticationModule'
        - 'CustomErrorModule'
        - 'DefaultDocumentModule'
        - 'DirectoryListingModule'
        - 'FileCacheModule'
        - 'HttpCacheModule'
        - 'HttpLoggingModule'
        - 'ProtocolSupportModule'
        - 'RequestFilteringModule'
        - 'StaticCompressionModule'
        - 'StaticFileModule'
        - 'TokenCacheModule'
        - 'UriCacheModule'
filter_main_remove:
    NewValue: ''
condition: selection and not 1 of filter_main_*

False positives (as the rule lists them)

• Legitimate administrator activity

Tags

• attack.persistence
• attack.defense-impairment
• attack.t1685.001
• attack.t1505.004

MITRE ATT&CK ids this rule names

• T1505.004
• T1685.001

References

• https://learn.microsoft.com/en-us/iis/manage/provisioning-and-managing-iis/configure-logging-in-iis
• https://www.microsoft.com/en-us/security/blog/2022/12/12/iis-modules-the-evolution-of-web-shells-and-how-to-detect-them/
• https://www.microsoft.com/en-us/security/blog/2022/07/26/malicious-iis-extensions-quietly-open-persistent-backdoors-into-servers/
• https://learn.microsoft.com/en-us/iis/get-started/introduction-to-iis/iis-modules-overview

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/builtin/iis-configuration/win_iis_module_added.yml