Detection: Splunk DoS via POST Request Datamodel Endpoint

Updated Date: 2024-07-01 ID: 45766810-dbb2-44d4-b889-b4ba3ee0d1f5 Author: Rod Soto Type: Hunting Product: Splunk Enterprise Security

Description

The following is a hunting search that allows investigation of error messages indicating Splunk HTTP engine shutdown as a result of a crafted posted request against '/datamodel/model' endpoint.

1`splunkd_webs` log_level=INFO message="ENGINE: HTTP Server cherrypy._cpwsgi_server.CPWSGIServer(('127.0.0.1', 8065)) shut down"  
2| stats count min(_time) as firstTime max(_time) as lastTime by splunk_server message  
3| `security_content_ctime(firstTime)` 
4| `security_content_ctime(lastTime)` 
5| `splunk_dos_via_post_request_datamodel_endpoint_filter`

Data Source

Name Platform Sourcetype Source Supported App
N/A N/A N/A N/A N/A

Macros Used

Name Value
security_content_ctime convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$)
splunk_dos_via_post_request_datamodel_endpoint_filter search *
splunk_dos_via_post_request_datamodel_endpoint_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
T1499 Endpoint Denial of Service Impact
KillChainPhase.ACTIONS_ON_OBJECTIVES
NistCategory.DE_AE
Cis18Value.CIS_10
Sandworm Team

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 Risk Event False
This configuration file applies to all detections of type hunting.

Implementation

Need access to the internal indexes.

Known False Positives

This is a hunting search and will produce false positives as other causes can also shut down splunk HTTP engine, however this denial of service error is associated to a request to the datamodel/model endpoing which operator can research and find proximity of request and message in logs.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message Risk Score Impact Confidence
Possible Denial of Service attack against $splunk_server$ 50 100 50
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

References

Detection Testing

Test Type Status Dataset Source Sourcetype
Validation ✅ Passing N/A N/A N/A
Unit ✅ Passing Dataset /opt/splunk/var/log/splunk/web_service.log splunk_web_service
Integration ✅ Passing Dataset /opt/splunk/var/log/splunk/web_service.log splunk_web_service

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