Detection rules › Splunk
Suspicious Certificate Authentication (Windows Event Log)
Adversaries may steal an AD CA’s root certificate, and forge a certificate for any active user or computer. This use case looks for Kerberos ticket requests with certificate thumbprints.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Persistence | |
| Defense Impairment | |
| Credential Access |
References
Telemetry coverage
| Provider | Record / event type |
|---|---|
| Security-Auditing | Event ID 4768: A Kerberos authentication ticket (TGT) was requested. |
Rule body
id: '8651.11135'
title: Suspicious Certificate Authentication
description: 'Adversaries may steal an AD CA’s root certificate, and forge a certificate
for any active user or computer. This use case looks for Kerberos ticket requests
with certificate thumbprints. '
logic_format: Splunk
logic: ' `get_endpoint_data` `get_endpoint_data_winevent` (TERM(EventCode=4768) OR
"<EventID>4768<") Certificate_Issuer_Name=* | eval certificate_name=Certificate_Issuer_Name
| table _time, host, user process, process_*, parent_process, parent_process_*,
src_*, dest_*, subject, certificate_* | bin span=1s | stats values(*) as * by _time,
host '
techniques:
- persistence:modify authentication process
technique_id:
- T1556
data_category:
- Windows event logs
references:
- https://www.specterops.io/assets/resources/Certified_Pre-Owned.pdf
Stages and Predicates
Stage 1: search
`get_endpoint_data` `get_endpoint_data_winevent` (TERM(EventCode=4768) OR "<EventID>4768<") Certificate_Issuer_Name=*
Stage 2: eval
| eval certificate_name=Certificate_Issuer_Name
Stage 3: table
| table _time, host, user process, process_*, parent_process, parent_process_*, src_*, dest_*, subject, certificate_*
Stage 4: bucket
| bin span=1s
Stage 5: stats
| stats values(*) as * by _time, host
Indicators
These rows show field, operator, and value matches.
| Field | Kind | Values | Search |
|---|---|---|---|
Certificate_Issuer_Name | eq |
| field:"Certificate_Issuer_Name" kind:eq value:"*" |
EventCode | eq |
| field:"EventID" kind:eq value:"4768" |
Search terms
These SPL tokens match against raw event text.
| Stage | Term |
|---|---|
| 1 | "<EventID>4768<" |