Implementing Endpoint Detection With Wazuh

Implementing Endpoint Detection with Wazuh

Overview

Wazuh is an open-source SIEM and XDR platform for endpoint monitoring, threat detection, and compliance. This skill covers managing agents via the Wazuh REST API, creating custom decoders and rules in XML for organization-specific detections, querying alerts, and testing rule logic using the logtest endpoint.

When to Use

• When deploying or configuring implementing endpoint detection with wazuh capabilities in your environment
• When establishing security controls aligned to compliance requirements
• When building or improving security architecture for this domain
• When conducting security assessments that require this implementation

Common Misconfigurations & Verification

• Agent registered but not enrolled/connected: agent_control -l or GET /agents?status=disconnected shows Never connected/disconnected. Usually a 1514/udp (enrollment 1515/tcp) block or a stale key. Re-key with manage_agents and confirm Agent ... is now active in /var/ossec/logs/ossec.log.
• Custom rule/decoder silently not firing: rules in /var/ossec/etc/rules/local_rules.xml need a matching decoder first. Validate with /var/ossec/bin/wazuh-logtest (or the /logtest API) — "Phase 2: completed decoding" with no extracted fields means your decoder regex/prematch missed, so the rule never evaluates.
• Rule ID collision / level 0: custom rule id must be 100000–120000 and level > 0, or the alert is dropped before reaching the indexer.
• Confirm a hit end to end: feed a known-bad line through logtest, then GET /alerts (or query the wazuh-alerts-* index) for that rule ID. No index document means the analysisd→filebeat→indexer path (template/ingest) is broken, not your rule.
• Active response never runs: check <command>/<active-response> location and ossec-execd logs; a missing executable on the agent OS fails silently.

Prerequisites

• Wazuh Manager 4.x deployed with API enabled
• Python 3.9+ with requests library
• API credentials (username/password for JWT authentication)
• Understanding of Wazuh decoder and rule XML syntax

Steps

Step 1: Authenticate to Wazuh API

Obtain JWT token via POST to /security/user/authenticate.

Step 2: List and Monitor Agents

Query agent status, versions, and last keep-alive via /agents endpoint.

Step 3: Query Security Alerts

Search alerts by rule ID, severity, agent, or time range.

Step 4: Test Custom Rules with Logtest

Use the /logtest endpoint to validate decoder and rule logic against sample log lines.

Expected Output

JSON report with agent inventory, alert statistics, rule coverage, and logtest validation results.