Sigma rule: Uncommon New Firewall Rule Added In Windows Firewall Exception List

Rule

Title

Uncommon New Firewall Rule Added In Windows Firewall Exception List

Status

test

Level

medium

Author

frack113

Date

2022-02-19

Modified

2026-08-27

File

rules/windows/builtin/firewall_as/win_firewall_as_add_rule.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects when a rule has been added to the Windows Firewall exception list

Log source

product

windows

service

firewall-as

Detection

selection:
    EventID:
        - 2004 # A rule has been added to the Windows Defender Firewall exception list
        - 2071 # A rule has been added to the Windows Defender Firewall exception list. (Windows 11)
        - 2097
filter_main_block:
    Action: 2 # Block
filter_main_generic:
    ApplicationPath|startswith:
        - 'C:\Program Files (x86)\'
        - 'C:\Program Files\'
        - 'C:\Windows\System32\'
        - 'C:\Windows\SysWOW64\'
        - 'C:\Windows\WinSxS\'
filter_main_covered_paths:
    # This filter is added to avoid duplicate alerting from 9e2575e7-2cb9-4da1-adc8-ed94221dca5e
    ApplicationPath|contains:
        - 'C:\PerfLogs\'
        - 'C:\Temp\'
        - 'C:\Tmp\'
        - 'C:\Users\Public\'
        - 'C:\Windows\Tasks\'
        - 'C:\Windows\Temp\'
        - '\AppData\Local\Temp\'
filter_main_system:
    ApplicationPath: 'SYSTEM'
    ModifyingApplication:
        - 'C:\Windows\System32\dllhost.exe'
        - 'C:\Windows\System32\oobe\Setup.exe'
        - 'C:\Windows\System32\svchost.exe'
filter_main_ehome:
    ApplicationPath|startswith: 'C:\Windows\ehome\'
    ModifyingApplication: 'C:\Windows\System32\oobe\Setup.exe'
filter_main_tiworker:
    ModifyingApplication|startswith: 'C:\Windows\WinSxS\'
    ModifyingApplication|endswith: '\TiWorker.exe'
filter_main_null:
    ApplicationPath: null
filter_optional_no_path:
    # This filter filters a lot of FPs related to Windows Services
    ModifyingApplication:
        - 'C:\Windows\System32\svchost.exe'
        - 'C:\Windows\System32\dllhost.exe'
    ApplicationPath: ''
filter_optional_msmpeng:
    - ModifyingApplication|startswith:
          - 'C:\ProgramData\Microsoft\Windows Defender\Platform\'
          - 'C:\Program Files\Windows Defender\'
      ModifyingApplication|endswith: '\MsMpEng.exe'
    - ApplicationPath|startswith:
          - 'C:\ProgramData\Microsoft\Windows Defender\Platform\'
          - 'C:\Program Files\Windows Defender\'
      ApplicationPath|endswith: '\MsMpEng.exe'
filter_optional_systemApps:
    ApplicationPath|startswith: 'C:\Windows\SystemApps\'
    ModifyingApplication: 'C:\Windows\System32\svchost.exe'
condition: selection and not 1 of filter_main_* and not 1 of filter_optional_*

Tags

• attack.defense-impairment
• attack.t1686.003

MITRE ATT&CK ids this rule names

• T1686.003

References

• https://learn.microsoft.com/en-us/previous-versions/windows/it-pro/windows-server-2008-r2-and-2008/dd364427(v=ws.10)

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/firewall_as/win_firewall_as_add_rule.yml