Uncommon Outbound Kerberos Port 88 Network Connections (Windows Security Event 5156)
Alerts on rare outbound Kerberos (port 88) connections from non-browser/non-lsass processes using Windows Event 5156.
- Product
- windows
- Service
- security
- Author
- Ilyas Ochkov, oscd.community (SigmaHQ), DRL 1.1
- Published
- 2019-10-24
- Updated
- 2026-07-31
ATT&CK techniques
Cred AccessRecon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact
What it detects
This rule flags Windows Security Event 5156 instances where an outbound connection targets destination port 88, which indicates Kerberos traffic to an external host. Such activity can be relevant for attacker behaviors like lateral movement or credential-access techniques involving delegation. The detection relies on event telemetry containing the process image path and destination port, and it excludes connections originating from typical local system paths used by lsass.exe and common browser executables.
Reporting behind it
Changelog
v2- v2Candidate ingested via manual entry.2026-07-31
- v1No changelog recorded for this version.2026-07-30
Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.
title: Uncommon Outbound Kerberos Port 88 Network Connections (Windows Security Event 5156)
id: bc013751-e853-4e41-ae11-3c01ade3ef61
related:
- id: e54979bd-c5f9-4d6c-967b-a04b19ac4c74
type: similar
- id: eca91c7c-9214-47b9-b4c5-cb1d7e4f2350
type: derived
status: test
description: This rule flags Windows Security Event 5156 instances where an outbound connection targets destination port 88, which indicates Kerberos traffic to an external host. Such activity can be relevant for attacker behaviors like lateral movement or credential-access techniques involving delegation. The detection relies on event telemetry containing the process image path and destination port, and it excludes connections originating from typical local system paths used by lsass.exe and common browser executables.
references:
- https://github.com/GhostPack/Rubeus
- https://github.com/SigmaHQ/sigma/blob/master/rules/windows/builtin/security/win_security_susp_outbound_kerberos_connection.yml
author: Ilyas Ochkov, oscd.community, Huntrule Team
date: 2019-10-24
modified: 2024-03-15
tags:
- attack.lateral-movement
- attack.credential-access
- attack.t1558.003
logsource:
product: windows
service: security
detection:
selection:
EventID: 5156
DestPort: 88
filter_main_lsass:
Application|startswith:
- \device\harddiskvolume
- "C:"
Application|endswith: \Windows\System32\lsass.exe
filter_optional_chrome:
Application|startswith:
- \device\harddiskvolume
- "C:"
Application|endswith:
- \Program Files (x86)\Google\Chrome\Application\chrome.exe
- \Program Files\Google\Chrome\Application\chrome.exe
filter_optional_firefox:
Application|startswith:
- \device\harddiskvolume
- "C:"
Application|endswith:
- \Program Files (x86)\Mozilla Firefox\firefox.exe
- \Program Files\Mozilla Firefox\firefox.exe
filter_optional_tomcat:
Application|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
license: DRL-1.1