How to Build a SIEM (Security Information & Event Management) System in 2025

Irfan Alam August 7, 2025 36 views

Introduction

In 2025, cyberattacks are more complex than ever, making Security Information and Event Management (SIEM) a crucial tool for organizations. A SIEM solution helps you collect, analyze, and act on security data in real-time. This tutorial will guide you step-by-step in building a SIEM system for enterprise-level monitoring and threat detection.

Step 1: Define Your SIEM Goals

Start with clear objectives:

Detect and respond to threats in real-time.
Maintain compliance (PCI-DSS, GDPR, HIPAA).
Centralize log management from multiple sources.

Step 2: Choose the Right SIEM Platform

Options in 2025:

Open Source: ELK Stack (Elasticsearch, Logstash, Kibana), Wazuh.
Commercial: Splunk, IBM QRadar, Microsoft Sentinel.

We’ll use ELK + Wazuh in this tutorial for cost-effective enterprise-grade monitoring.

Step 3: Deploy Elasticsearch for Log Storage

sudo apt update && sudo apt install elasticsearch -y
sudo systemctl enable elasticsearch --now

Configure /etc/elasticsearch/elasticsearch.yml for cluster settings.

Step 4: Set Up Logstash for Data Collection

sudo apt install logstash -y

Edit /etc/logstash/conf.d/input.conf:

input {
  beats {
    port => 5044
  }
}

Step 5: Install and Configure Wazuh

Wazuh adds intrusion detection and security analytics:

curl -sO https://packages.wazuh.com/key/GPG-KEY-WAZUH
sudo apt install wazuh-manager -y

Configure /var/ossec/etc/ossec.conf for agents and rules.

Step 6: Configure Beats for Log Forwarding

Install Filebeat on endpoints:

sudo apt install filebeat -y

Edit /etc/filebeat/filebeat.yml to send logs to Logstash.

Step 7: Visualize with Kibana

sudo apt install kibana -y
sudo systemctl enable kibana --now

Access via http://server-ip:5601 and configure dashboards for Wazuh.

Step 8: Create Custom Alerts

Use Wazuh rules and Elastic alerts to detect anomalies like failed login attempts or privilege escalations.

Step 9: Automate Incident Response

Integrate SOAR (Security Orchestration, Automation, and Response) tools to trigger actions like blocking malicious IPs.

Step 10: Regularly Tune and Optimize

Update correlation rules, review false positives, and scale storage as logs grow.

Conclusion

By combining ELK Stack with Wazuh, you can build a powerful, cost-effective SIEM system in 2025 that provides real-time visibility into threats and helps you respond faster to security incidents.