GitHub Repo

Detection: Splunk DoS Using Malformed SAML Request

REMOVED DETECTION

This detection has been removed from the Splunk Threat Research content library and is no longer maintained or supported.

Reason: Detection is deprecated as the associated CVEs have been patched in the latest Splunk release.

Removed in version: 5.6.0

If you have any questions or concerns, please reach out to us at research@splunk.com.

Updated Date: 2026-05-14 ID: 8e8a86d5-f323-4567-95be-8e817e2baee6 Author: Rod Soto Type: Hunting Product: Splunk Enterprise Security

Description

The following analytic detects a denial of service (DoS) attempt using a malformed SAML request targeting the /saml/acs REST endpoint in Splunk Enterprise versions lower than 9.0.6 and 8.2.12. It leverages splunkd logs, specifically looking for error messages containing "xpointer" in the expr field. This activity is significant because it can cause the Splunk daemon to crash or hang, disrupting service availability. If confirmed malicious, this attack could lead to prolonged downtime, impacting the organization's ability to monitor and respond to security events.

1`splunkd` event_message=*error* expr=*xpointer* 
2| stats count min(_time) as firstTime max(_time) as lastTime by component expr splunk_server event_message 
3| `security_content_ctime(firstTime)`
4| `security_content_ctime(lastTime)` 
5| `splunk_dos_using_malformed_saml_request_filter`

Data Source

Name Platform Sourcetype Source
Splunk Splunk icon Splunk 'splunkd_ui_access' 'splunkd_ui_access.log'

Macros Used

Name Value
splunkd index=_internal sourcetype=splunkd
splunk_dos_using_malformed_saml_request_filter ``
splunk_dos_using_malformed_saml_request_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
T1498 Network Denial of Service Impact

Default Configuration

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

Setting Value
Disabled true
Cron Schedule N/A
Earliest Time N/A
Latest Time N/A
Schedule Window N/A
Creates Finding (Notable) No
Creates Intermediate Finding (Risk Event) No
Hunting detections do not generate a Finding (Notable) or Intermediate Findings (Risk Events).

Implementation

To run this search, you must have access to the _internal index.

Known False Positives

This search will show false positives. The analyst must look for errors and a pointer indicating a malicious file.

Associated Analytic Story

References

Detection Testing

Test Type Status Dataset Source Sourcetype
Validation Not Applicable N/A N/A N/A
Unit Not Applicable N/A N/A N/A

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: 6