DNS Kerberos Coercion

name: DNS Kerberos Coercion
id: 8551252d-b5b6-4b6e-8a82-51460aeb29a3
version: 5
creation_date: '2025-11-18'
modification_date: '2026-05-13'
author: Raven Tait, Splunk
status: production
type: TTP
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.
data_source:
    - Suricata
    - Sysmon EventID 22
search: |-
    | 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
    | `drop_dm_object_name(DNS)`
    | `security_content_ctime(firstTime)`
    | `security_content_ctime(lastTime)`
    | table firstTime lastTime query count src dest
    | `dns_kerberos_coercion_filter`
how_to_implement: 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.
references:
    - https://web.archive.org/web/20250617122747/https://www.synacktiv.com/publications/ntlm-reflection-is-dead-long-live-ntlm-reflection-an-in-depth-analysis-of-cve-2025
    - https://www.synacktiv.com/publications/relaying-kerberos-over-smb-using-krbrelayx
    - https://www.guidepointsecurity.com/blog/the-birth-and-death-of-loopyticket/
finding:
    title: A dns query $query$ with marshalled CREDENTIAL_TARGET_INFORMATION seen from $src$
    entity:
        field: src
        type: system
        score: 50
analytic_story:
    - Compromised Windows Host
    - Suspicious DNS Traffic
    - Local Privilege Escalation With KrbRelayUp
    - Kerberos Coercion with DNS
asset_type: Endpoint
cve:
    - CVE-2025-33073
mitre_attack_id:
    - T1557.001
    - T1187
    - T1071.004
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: network
security_domain: network