| ID | Technique | Tactic |
|---|---|---|
| T1557.001 | LLMNR/NBT-NS Poisoning and SMB Relay | Collection |
| T1187 | Forced Authentication | Credential Access |
| T1071.004 | DNS | Credential Access |
Detection: Windows Credential Target Information Structure in Commandline
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 process creation events looking for specific CREDENTIAL_TARGET_INFORMATION structures.
Search
1
2| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.process="*1UWhRCA*" Processes.process="*AAAAA*" Processes.process="*YBAAAA*" by Processes.action Processes.dest Processes.original_file_name Processes.parent_process Processes.parent_process_exec Processes.parent_process_guid Processes.parent_process_id Processes.parent_process_name Processes.parent_process_path Processes.process Processes.process_exec Processes.process_guid Processes.process_hash Processes.process_id Processes.process_integrity_level Processes.process_name Processes.process_path Processes.user Processes.user_id Processes.vendor_product
3| `drop_dm_object_name(Processes)`
4| `security_content_ctime(firstTime)`
5| `security_content_ctime(lastTime)`
6| `windows_credential_target_information_structure_in_commandline_filter`
Data Source
| Name | Platform | Sourcetype | Source |
|---|---|---|---|
| Sysmon EventID 1 | 'XmlWinEventLog' |
'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational' |
Macros Used
| Name | Value |
|---|---|
| security_content_ctime | convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$) |
| windows_credential_target_information_structure_in_commandline_filter | search * |
windows_credential_target_information_structure_in_commandline_filter is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
Annotations
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 |
Implementation
The detection is based on data that originates from Endpoint Detection and Response (EDR) agents. These agents are designed to provide security-related telemetry from the endpoints where the agent is installed. To implement this search, you must ingest logs that contain the process GUID, process name, and parent process. Additionally, you must ingest complete command-line executions. These logs must be processed using the appropriate Splunk Technology Add-ons that are specific to the EDR product. The logs must also be mapped to the Processes node of the Endpoint data model. Use the Splunk Common Information Model (CIM) to normalize the field names and speed up the data modeling process.
Known False Positives
Commands with all of these base64 encoded values are unusual in production environments. Filter as needed.
Associated Analytic Story
Risk Based Analytics (RBA)
Risk Message:
An instance of CREDENTIAL_TARGET_INFORMATION magic string was identified in a command on endpoint $dest$ by user $user$.
| Risk Object | Risk Object Type | Risk Score | Threat Objects |
|---|---|---|---|
| user | user | 44 | No Threat Objects |
| dest | system | 44 | No Threat Objects |
References
-
https://www.synacktiv.com/publications/relaying-kerberos-over-smb-using-krbrelayx
-
https://www.guidepointsecurity.com/blog/the-birth-and-death-of-loopyticket/
Detection Testing
| Test Type | Status | Dataset | Source | Sourcetype |
|---|---|---|---|---|
| Validation | ✅ Passing | N/A | N/A | N/A |
| Unit | ✅ Passing | Dataset | XmlWinEventLog:Microsoft-Windows-Sysmon/Operational |
XmlWinEventLog |
| Integration | ✅ Passing | Dataset | XmlWinEventLog:Microsoft-Windows-Sysmon/Operational |
XmlWinEventLog |
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