🌍 Real-World Case Study: How IDS, IPS, and SIEM Work Together

Attack on an E-Commerce Company (CyberMart Inc.)

Background

CyberMart Inc. runs a large online shopping platform. Their network security stack includes:

• IDS (Snort) → Detects threats

• IPS (Palo Alto Firewall) → Blocks malicious traffic

• SIEM (Splunk Enterprise Security) → Collects logs, correlates attacks, sends alerts

⚠️ Attack Scenario

On a Monday morning, CyberMart sees unusual traffic.

1. Attacker attempts a SQL Injection

An attacker sends hundreds of requests to this vulnerable URL:

https://cybermart.com/product?id=10 OR 1=1--

How Systems React

System	Action
IDS (Snort)	Detects SQL Injection pattern → Sends alert
IPS (Firewall)	Blocks repeated malicious requests
SIEM (Splunk)	Correlates alerts across multiple logs, escalates incident

📡 Detailed Step-By-Step Sequence

Step 1 — IDS Detects the Attack

The IDS generates the following alert:

Alert: SQL Injection attempt detected from IP 192.168.44.23

IDS does not block, but sends the alert to the SOC team.

Step 2 — IPS Blocks the Attack

IPS sees repeated malicious traffic → automatically blocks the attacker’s IP.

Action: Blocked traffic from 192.168.44.23 for violation: SQL Injection Rule

This prevents damage in real time.

Step 3 — SIEM Correlates and Analyzes

SIEM collects logs from:

• IDS alerts

• IPS block logs

• Web server logs

• Database logs

The SIEM correlates multiple alerts from different systems and generates a single high-priority incident:

Correlation Rule Triggered:

Multiple SQL Injection attempts + IPS Block + Server Log Errors

Severity: High

Incident ID: 2025-00199

SIEM then:

• Sends alerts to on-call security engineers

• Creates a case in incident-management system

• Displays metrics and graphs on dashboards

Step 4 — SOC Team Investigation

SOC analysts open the SIEM dashboard and check:

• Attack timeline

• Source IP and geolocation

• Affected endpoints

• Pattern of malicious queries

They confirm the IPS successfully neutralized the threat.

Step 5 — Remediation

Team takes further steps:

• Patch the vulnerable SQL endpoint

• Strengthen WAF rules

• Update IPS signatures

• Add a new SIEM correlation rule

🧠 What This Case Study Teaches

This real-world flow shows how:

IDS → detects

IPS → prevents

SIEM → analyzes and correlates

Together, they form a complete security ecosystem.

🏗️ Why SIEM is Critical

SIEM acts as the brain of the security system.

SIEM Responsibilities

• Collect logs from all devices

• Correlate related alerts

• Reduce false alarms

• Create incidents

• Provide dashboards, timelines, and reports

• Trigger automated responses (SOAR)

Without SIEM, IDS and IPS data stays isolated — making it hard to see the big picture.