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Description

The following analytic identifies a process performing an outbound connection on port 88 used by default by the network authentication protocol Kerberos. Typically, on a regular Windows endpoint, only the lsass.exe process is the one tasked with connecting to the Kerberos Distribution Center to obtain Kerberos tickets. Identifying an unknown process using this protocol may be evidence of an adversary abusing the Kerberos protocol.

  • Type: TTP
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint, Network_Traffic
  • Last Updated: 2022-03-09
  • Author: Mauricio Velazco, Splunk
  • ID: c91a0852-9fbb-11ec-af44-acde48001122

Annotations

ATT&CK
ID Technique Tactic
T1550 Use Alternate Authentication Material Defense Evasion, Lateral Movement
Kill Chain Phase
  • Reconnaissance
NIST
CIS20
CVE
1
2
3
4
5
6
7
8
9
10
| tstats `security_content_summariesonly` count FROM datamodel=Endpoint.Processes where Processes.process_name!=lsass.exe by _time Processes.process_id Processes.process_name Processes.dest Processes.process_path Processes.process Processes.parent_process_name 
| `drop_dm_object_name(Processes)` 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| join  process_id [
| tstats `security_content_summariesonly` count FROM datamodel=Network_Traffic.All_Traffic where All_Traffic.dest_port = 88 by All_Traffic.process_id All_Traffic.dest All_Traffic.dest_port 
| `drop_dm_object_name(All_Traffic)` ] 
| table _time dest parent_process_name process_name process_path process process_id dest_port 
| `unknown_process_using_the_kerberos_protocol_filter`

Macros

The SPL above uses the following Macros:

Note that unknown_process_using_the_kerberos_protocol_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required field

  • _time
  • All_Traffic.dest_ip
  • All_Traffic.dest_port
  • All_Traffic.src_ip
  • Processes.process_id
  • Processes.process_name
  • Processes.dest
  • Processes.process_path
  • Processes.process
  • Processes.parent_process_name

How To Implement

To successfully implement this search, you must be ingesting your endpoint events and populating the Endpoint and Network data models.

Known False Positives

Custom applications may leverage the Kerberos protocol. Filter as needed.

Associated Analytic story

RBA

Risk Score Impact Confidence Message
36.0 60 60  

Reference

Test Dataset

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

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