Linux Auditd Auditd Daemon Start

name: Linux Auditd Auditd Daemon Start
id: 6b0cb0ff-9a7e-4475-a687-43827fdb31d6
version: 6
creation_date: '2024-08-12'
modification_date: '2026-05-13'
author: Teoderick Contreras, Splunk
status: production
type: Anomaly
description: The following analytic detects the (re)initialization of the Linux audit daemon (auditd) by identifying log entries of type DAEMON_START. This event indicates that the audit subsystem has resumed logging after being stopped or has started during system boot. While DAEMON_START may be expected during reboots or legitimate configuration changes, it can also signal attempts to re-enable audit logging after evasion, or restarts with modified or reduced rule sets. Monitoring this event in correlation with DAEMON_END, DAEMON_ABORT, and auditctl activity provides visibility into the continuity and integrity of audit logs. Frequent or unexplained DAEMON_START events should be investigated, especially if they are not accompanied by valid administrative or system activity.
data_source:
    - Linux Auditd Daemon Start
search: |-
    `linux_auditd` type=DAEMON_START
      | rename host as dest
      | stats count min(_time) as firstTime max(_time) as lastTime
        BY type op res
           auid dest pid
      | `security_content_ctime(firstTime)`
      | `security_content_ctime(lastTime)`
      | `linux_auditd_auditd_daemon_start_filter`
how_to_implement: To implement this detection, the process begins by ingesting auditd data, that consist SYSCALL, TYPE, EXECVE and PROCTITLE events, which captures command-line executions and process details on Unix/Linux systems. These logs should be ingested and processed using Splunk Add-on for Unix and Linux (https://splunkbase.splunk.com/app/833), which is essential for correctly parsing and categorizing the data. The next step involves normalizing the field names  to match the field names set by the Splunk Common Information Model (CIM) to ensure consistency across different data sources and enhance the efficiency of data modeling. This approach enables effective monitoring and detection of linux endpoints where auditd is deployed
known_false_positives: Administrator or network operator can use this application for automation purposes. Please update the filter macros to remove false positives.
references:
    - https://docs.redhat.com/en/documentation/red_hat_enterprise_linux/6/html/security_guide/sec-audit_record_types
intermediate_findings:
    entities:
        - field: dest
          type: system
          score: 20
          message: Auditd service event - [$type$] event occurred on host - [$dest$].
analytic_story:
    - Compromised Linux Host
asset_type: Endpoint
mitre_attack_id:
    - T1685.004
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: endpoint
security_domain: endpoint