GitHub Repo

Detection: Splunk XSS in Highlighted JSON Events

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This detection has been removed from the Splunk Threat Research content library and is no longer maintained or supported.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: 1030bc63-0b37-4ac9-9ae0-9361c955a3cc Author: Rod Soto, Splunk Type: Hunting Product: Splunk Enterprise Security

Description

The following analytic identifies potential exploitation of a Cross-Site Scripting (XSS) vulnerability in Splunk Enterprise 9.1.2. It detects suspicious requests to the Splunk web GUI that may execute JavaScript within script tags. This detection leverages logs from the splunkd_ui data source, focusing on specific URI paths and HTTP methods. This activity is significant as it can allow attackers to execute arbitrary JavaScript, potentially accessing the API with the logged-in user's permissions. If the user is an admin, the attacker could create an admin account, leading to full control over the Splunk environment.

1`splunkd_ui` "/*/splunkd/__raw/servicesNS/nobody/search/authentication/users" status=201 
2| stats count min(_time) as firstTime max(_time) as lastTime by clientip, uri_path, method 
3| `security_content_ctime(firstTime)` 
4| `security_content_ctime(lastTime)` 
5| `splunk_xss_in_highlighted_json_events_filter`

Data Source

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

Macros Used

Name Value
splunkd_ui index=_internal sourcetype=splunkd_ui_access
splunk_xss_in_highlighted_json_events_filter ``
splunk_xss_in_highlighted_json_events_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
T1189 Drive-by Compromise Initial Access

CVE

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

This search only applies to web-GUI-enabled Splunk instances and operator must have access to internal indexes.

Known False Positives

This is a hunting search and will produce false positives as it is not possible to view contents of a request payload. It shows the artifact resulting from a potential exploitation payload (the creation of a user with admin privileges).

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: 7