Unusual Outbound Kerberos Connection (via network_connection)

title: Unusual Outbound Kerberos Connection (via network_connection)
id: 4925db93-e33a-54e1-ad21-d0fb30c27f39
status: stable
description: This rule detects uncommon outbound network behavior via Kerberos default port suggesting possible lateral movement or first stage PrivEsc via delegation.
references:
    - https://attack.mitre.org/techniques/T1550/003/
    - https://attack.mitre.org/techniques/T1558/
    - https://github.com/GhostPack/Rubeus
author: Huntrule Team
date: 2026-03-07
tags:
    - attack.credential-access
    - attack.t1558
    - attack.lateral-movement
    - attack.t1550.003
logsource:
    category: network_connection
    product: windows
detection:
    selection:
        DestinationPort: 88
        Initiated: 'true'
    filter_main_lsass:
        Image: 'C:\Windows\System32\lsass.exe'
    filter_optional_chrome:
        Image:
            - 'C:\Program Files (x86)\Google\Chrome\Application\chrome.exe'
            - 'C:\Program Files\Google\Chrome\Application\chrome.exe'
    filter_optional_firefox:
        Image:
            - 'C:\Program Files (x86)\Mozilla Firefox\firefox.exe'
            - 'C:\Program Files\Mozilla Firefox\firefox.exe'
    filter_optional_tomcat:
        Image|endswith: '\tomcat\bin\tomcat8.exe'
    filter_hr:
        Image:
            - C:\Program Files (x86)\Microsoft\Edge\Application\msedge.exe
            - C:\Program Files\Microsoft\Edge\Application\msedge.exe
    condition: (selection and not 1 of filter_main_* and not 1 of filter_optional_*) and not filter_hr
falsepositives:
    - Unknown
level: medium