Wazuh Agent for Linux - Comprehensive Security Monitoring Guide

Published: at 08:30 AM

Wazuh Agent for Linux: Comprehensive Security Monitoring Guide

The Wazuh agent is a lightweight yet powerful security monitoring component that transforms Linux endpoints into intelligent security sensors. As part of the broader Wazuh XDR/SIEM platform, it provides real-time visibility into security events while maintaining minimal resource overhead.

Architecture Overview

The Wazuh security platform consists of four key components:

  1. Wazuh Agent - Endpoint monitoring component (covered in this guide)
  2. Wazuh Server - Central management, analysis, and rule processing
  3. Wazuh Indexer - Data storage and search capabilities
  4. Wazuh Dashboard - Visualization and configuration interface

The agent communicates with the central server through an encrypted, authenticated channel, ensuring secure transmission of security telemetry even across untrusted networks.

Resource Requirements

One of Wazuh agent’s key strengths is its lightweight footprint:

Core Security Capabilities

1. Log Collection and Analysis

The Wazuh agent excels at comprehensive log collection:

Configuration example for custom log collection:

<localfile>
  <log_format>syslog</log_format>
  <location>/var/log/custom-app/*.log</location>
</localfile>

2. File Integrity Monitoring (FIM)

FIM provides critical visibility into file system changes:

Key directories typically monitored:

3. System Call Monitoring

Leveraging the Linux Audit framework, Wazuh provides deep system-level visibility:

Example audit rules:

# Monitor privilege escalation
-a always,exit -F arch=b64 -S setuid -F a0=0 -F exe=/usr/bin/sudo -k privilege_escalation

# Track file access in sensitive directories
-w /etc/passwd -p wa -k passwd_changes

4. Security Configuration Assessment (SCA)

SCA performs automated security compliance checks:

Common checks include:

5. Vulnerability Detection

Proactive vulnerability management capabilities:

The agent collects package information from:

6. Malware and Rootkit Detection

Non-signature-based detection methods:

Detection techniques:

# Check for hidden processes
/var/ossec/bin/ossec-rootcheck

# Scan for rootkit signatures
/var/ossec/bin/rootkit_trojans.txt

7. Active Response Capabilities

Automated threat containment and remediation:

Example active response configuration:

<active-response>
  <command>firewall-drop</command>
  <location>local</location>
  <level>10</level>
  <timeout>600</timeout>
</active-response>

8. Container and Cloud Security

Modern infrastructure monitoring capabilities:

Deployment Best Practices

Installation Methods

  1. Package Managers: Native packages for major distributions
  2. Configuration Management: Ansible, Puppet, Chef modules available
  3. Container Deployment: Official Docker images for containerized environments
  4. Cloud Templates: Pre-configured images for cloud deployment

Security Hardening

  1. Agent Configuration: Restrict configuration file permissions
  2. Communication Security: Use certificate-based authentication
  3. Resource Limits: Configure appropriate thresholds
  4. Log Rotation: Implement proper log management
  5. Access Control: Limit who can manage agent configuration

Performance Optimization

  1. Scan Frequencies: Balance security with performance
  2. Exclusion Lists: Skip known-safe files and directories
  3. Buffer Sizes: Tune for your environment’s log volume
  4. Network Settings: Optimize compression and batch sizes

Integration with Security Operations

SIEM Integration

The Wazuh agent data can be integrated with:

Automation and Orchestration

Threat Detection Use Cases

1. Insider Threat Detection

2. Advanced Persistent Threats (APT)

3. Compliance Monitoring

4. Incident Response

Conclusion

The Wazuh agent represents a comprehensive security monitoring solution for Linux environments, providing defense-in-depth through multiple detection layers. Its lightweight design, combined with powerful detection capabilities and automated response features, makes it an excellent choice for organizations seeking to enhance their security posture without significant resource overhead.

By deploying Wazuh agents across your Linux infrastructure, you gain:

Whether protecting a single server or an entire data center, the Wazuh agent provides the foundation for a robust security monitoring program aligned with modern XDR principles.