IDS/IPS on Linux

1. Introduction

Intrusion Detection Systems (IDS) and Intrusion Prevention Systems (IPS) are vital components of network security. They monitor network traffic for suspicious activities and can take action to prevent breaches. This lesson will guide you through the implementation of these systems on Linux.

2. Key Concepts

• **Intrusion Detection System (IDS)**: Monitors network traffic and alerts administrators of potential threats.
• **Intrusion Prevention System (IPS)**: Monitors and actively prevents detected threats.
• **Signature-based Detection**: Identifies threats using predefined patterns (signatures).
• **Anomaly-based Detection**: Identifies threats by detecting deviations from normal behavior.

3. IDS vs IPS

Understanding the differences between IDS and IPS is crucial. Here are the key differences:

1. Function: IDS only detects and alerts; IPS detects and takes action.
2. Placement: IDS is typically placed outside the firewall; IPS is placed inline.
3. Response: IDS requires manual intervention; IPS can automatically block traffic.

4. Installation

We will use Snort, a popular open-source IDS/IPS system.

4.1 Install Snort

sudo apt update
sudo apt install snort
        

4.2 Verify Installation

snort -V
        

Ensure the version information is displayed correctly.

5. Configuration

5.1 Configure Snort

Configuration files are located in /etc/snort/snort.conf. You can edit this file to set up rules and network settings.

sudo nano /etc/snort/snort.conf
        

5.2 Set Up Rules

Rules define how Snort will behave. You can find example rules in /etc/snort/rules/.

sudo cp /etc/snort/rules/snort.conf /etc/snort/rules/snort-custom.conf
        

Edit snort-custom.conf to include your custom rules.

6. Best Practices

• Regularly update rules and signatures.
• Monitor logs for unusual activity.
• Test your IDS/IPS configuration regularly.
• Use a combination of detection methods for better coverage.

7. FAQ