GitHub Repo

Detection: Splunk DOS via printf search function

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This detection has been removed from the Splunk Threat Research content library and is no longer maintained or supported.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: 78b48d08-075c-4eac-bd07-e364c3780867 Author: Rod Soto, Eric McGinnis, Splunk Type: Hunting Product: Splunk Enterprise Security

Description

The following analytic identifies the use of the printf SPL function in Splunk searches, which can be exploited for a denial of service (DoS) attack. It detects this activity by querying the audit_searches data source for specific patterns involving makeresults, eval, fieldformat, and printf functions, excluding searches by the splunk_system_user. This activity is significant because it targets a known vulnerability in Splunk Enterprise versions lower than 8.1.14, 8.2.12, 9.0.6, and 9.1.1, potentially disrupting the availability of the Splunk instance. If confirmed malicious, this could lead to service outages and impact the monitoring and logging capabilities of the organization.

1`audit_searches` "*makeresults * eval * fieldformat *printf*" user!="splunk_system_user" search!="*audit_searches*" 
2| stats count by user splunk_server host search 
3| convert ctime(*time) 
4|`splunk_dos_via_printf_search_function_filter`

Data Source

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

Macros Used

Name Value
audit_searches index=_audit sourcetype=audittrail action=search
splunk_dos_via_printf_search_function_filter ``
splunk_dos_via_printf_search_function_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
T1499.004

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 requires the ability to search internal indexes.

Known False Positives

This search may produces false positives, analyst most focuse in the use of printf conversion function of eval to craft an expression that splunkd cannot interpret correctly causing it to crash.

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