Detection: DNS Kerberos Coercion

Updated Date: 2025-11-14 ID: 8551252d-b5b6-4b6e-8a82-51460aeb29a3 Author: Raven Tait, Splunk Type: TTP Product: Splunk Enterprise Security

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.

Search

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 where DNS.query="*1UWhRC*" DNS.query="*AAAAA*" DNS.query="*YBAAAA*" by DNS.answer DNS.answer_count DNS.query DNS.query_count DNS.reply_code_id DNS.src DNS.vendor_product 
3| `drop_dm_object_name(DNS)` 
4| `security_content_ctime(firstTime)` 
5| `security_content_ctime(lastTime)` 
6| table firstTime lastTime query count src dest 
7| `dns_kerberos_coercion_filter`

Data Source

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

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
T1557.001	LLMNR/NBT-NS Poisoning and SMB Relay	Collection
T1187	Forced Authentication	Credential Access
T1071.004	DNS	Credential Access

Command and Control

Exploitation

DE.CM

CIS 13

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 Notable	Yes
Rule Title	`%name%`
Rule Description	`%description%`
Notable Event Fields	user, dest
Creates Risk Event	True

This configuration file applies to all detections of type TTP. These detections will use Risk Based Alerting and generate Notable Events.

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

Risk Based Analytics (RBA)

Risk Message:

A dns query $query$ with marshalled CREDENTIAL_TARGET_INFORMATION seen from $src$

Risk Object	Risk Object Type	Risk Score	Threat Objects
src	system	56	No Threat Objects

References

Detection Testing

Test Type	Status	Dataset	Source	Sourcetype
Validation	✅ Passing	N/A	N/A	N/A
Unit	✅ Passing	Dataset	`Suricata`	`suricata`
Integration	✅ Passing	Dataset	`Suricata`	`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: 1