Try in Splunk Security Cloud

Description

In Splunk Enterprise versions lower than 9.0.6, and 8.2.12, an attacker can send a malformed security assertion markup language SAML request to the /saml/acs REST endpoint which can cause a denial of service through a crash or hang of the Splunk daemon.The SAML extensible markup language (XML) parser does not fail SAML signature validation when the attacker modifies the URI in the SAML request. Instead it attempts to access the modified URI, which causes the Splunk daemon to crash or hang.

  • Type: Hunting

  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud

  • Last Updated: 2023-09-05
  • Author: Rod Soto
  • ID: 8e8a86d5-f323-4567-95be-8e817e2baee6

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1498 Network Denial of Service Impact
Kill Chain Phase
  • Actions On Objectives
NIST
  • DE.AE
CIS20
  • CIS 10
CVE 


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

Macros

The SPL above uses the following Macros:

:information_source: splunk_dos_using_malformed_saml_request_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required fields

List of fields required to use this analytic.

  • component
  • expr
  • host
  • event_message

How To Implement

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

RBA

Risk Score Impact Confidence Message
15.0 50 30 Possible DoS attack against Splunk Server $splunk_server$

:information_source: The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

Reference

Test Dataset

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 | version: 1