Detection: DNS Kerberos Coercion

Description

Detects DNS-based Kerberos coercion attacks where adversaries inject marshaled credential structures into DNS records to spoof SPNs and redirect authentication such as in CVE-2025-33073. This detection leverages suricata looking for specific CREDENTIAL_TARGET_INFORMATION structures in DNS queries.

 1
 2| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime values(DNS.src) as src values(DNS.dest) as dest FROM datamodel=Network_Resolution
 3  WHERE DNS.query="*1UWhRC*" DNS.query="*AAAAA*" DNS.query="*YBAAAA*"
 4  BY DNS.answer DNS.answer_count DNS.query
 5     DNS.query_count DNS.reply_code_id DNS.src
 6     DNS.vendor_product
 7
 8| `drop_dm_object_name(DNS)`
 9
10| `security_content_ctime(firstTime)`
11
12| `security_content_ctime(lastTime)`
13
14| table firstTime lastTime query count src dest
15
16| `dns_kerberos_coercion_filter`

Data Source

Name Platform Sourcetype Source
Sysmon EventID 22 Windows icon Windows 'XmlWinEventLog' 'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational'
Suricata Other 'suricata' 'not_applicable'

Macros Used

Name Value
security_content_ctime convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$)
dns_kerberos_coercion_filter search *
dns_kerberos_coercion_filter is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Annotations

- MITRE ATT&CK
+ Kill Chain Phases
+ NIST
+ CIS
- Threat Actors
ID Technique Tactic
T1071.004 DNS Command and Control
T1187 Forced Authentication Credential Access
T1557.001 Name Resolution Poisoning and SMB Relay Collection
Exploitation
Command and Control
DE.CM
CIS 13

CVE

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Setting Value
Disabled true
Cron Schedule 0 * * * *
Earliest Time -70m@m
Latest Time -10m@m
Schedule Window auto
Creates Finding (Notable) Yes
Rule Title %name%
Rule Description %description%
Notable Event Fields user, dest
Creates Intermediate Finding (Risk Event) No
TTP detections generate a Finding (Notable) and may generate Intermediate Findings (Risk Events) for associated entities.

Implementation

To successfully implement this search, you will need to ensure that DNS data is populating the Network_Resolution data model.

Known False Positives

It's unlikely that a DNS entry contains the specific structure used by this attack. Filter as needed for your organization.

Associated Analytic Story

Finding

Title Entity Field Entity Type Risk Score
A dns query $query$ with marshalled CREDENTIAL_TARGET_INFORMATION seen from $src$ src system 50

References

Detection Testing

Test Type Status Dataset Source Sourcetype
Validation Passing N/A N/A N/A
Unit Passing Dataset not_applicable suricata
Integration ✅ Passing Dataset not_applicable suricata

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


Source: GitHub | Version: 5