Uncommon Outbound Kerberos Connection — Sigma Rule

Rule metadata and linked tags

Author: Ilyas Ochkov, oscd.community. Source status: test; severity: medium. Source dates: 2019-10-24 / 2024-03-15.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 04de6d48738862feb52d8a923d05d0f3795b770957cbaa10554940505074d935

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: Uncommon Outbound Kerberos Connection
id: e54979bd-c5f9-4d6c-967b-a04b19ac4c74
related:
    - id: eca91c7c-9214-47b9-b4c5-cb1d7e4f2350
      type: similar
status: test
description: |
    Detects uncommon outbound network activity via Kerberos default port indicating possible lateral movement or first stage PrivEsc via delegation.
references:
    - https://github.com/GhostPack/Rubeus
author: Ilyas Ochkov, oscd.community
date: 2019-10-24
modified: 2024-03-15
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'
    condition: selection and not 1 of filter_main_* and not 1 of filter_optional_*
falsepositives:
    - Web Browsers and third party application might generate similar activity. An initial baseline is required.
level: medium

Original YAML and metadata in JSON

False positives

• Web Browsers and third party application might generate similar activity. An initial baseline is required.

Source references

• https://github.com/GhostPack/Rubeus