name: Splunk DOS via printf search function
id: 78b48d08-075c-4eac-bd07-e364c3780867
version: 1
date: '2023-08-30'
author: Rod Soto, Eric McGinnis, Splunk
status: production
type: Hunting
data_source: []
description: This hunting search provides information on detecting a vulnerability In Splunk Enterprise versions lower than 8.1.14, 8.2.12, 9.0.6, and 9.1.1, an attacker can use the printf SPL function to perform a denial of service against the Splunk Enterprise instance.
search: '`audit_searches` "*makeresults * eval * fieldformat *printf*" user!="splunk_system_user" search!="*audit_searches*" 
  | stats count by user splunk_server host search 
  | convert ctime(*time) |`splunk_dos_via_printf_search_function_filter`'
how_to_implement: 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. 
references:
- https://advisory.splunk.com/
tags:
  analytic_story:
  - Splunk Vulnerabilities
  asset_type: endpoint
  confidence: 100
  impact: 100
  message: Possible denial of service attack against $host$
  cve:
  - CVE-2023-40594
  mitre_attack_id:
  - T1499.004
  observable:
  - name: host
    type: Hostname
    role:
    - Victim
  product:
  - Splunk Enterprise
  - Splunk Enterprise Security
  - Splunk Cloud
  risk_score: 100
  required_fields:
  - user 
  - splunk_server
  - host
  - search 
  security_domain: endpoint
tests:
- name: True Positive Test
  attack_data:
  - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1499.004/splunk/splunk_printf_abuse.log
    source: audittrail
    sourcetype: audittrail
    custom_index: _audit