# Snort 3 — Open-Source Network Intrusion Detection and Prevention System

> Snort 3 is a complete rewrite of the original Snort IDS/IPS, now maintained by Cisco. It performs real-time traffic analysis and packet logging, detecting threats using signature-based, protocol-analysis, and anomaly-based inspection methods on network traffic.

## Install

Save as a script file and run:

# Snort 3 — Open-Source Network Intrusion Detection and Prevention System

## Quick Use
```bash
# Install on Ubuntu
sudo apt install snort3
# Or build from source
git clone https://github.com/snort3/snort3.git
cd snort3 && mkdir build && cd build
cmake .. -DCMAKE_INSTALL_PREFIX=/usr/local && make -j$(nproc) && sudo make install
# Run in IDS mode on an interface
sudo snort -c /usr/local/etc/snort/snort.lua -i eth0 -A alert_fast
```

## Introduction
Snort 3 is a next-generation network intrusion detection and prevention system that analyzes network traffic in real time. Originally created in 1998, Snort is one of the most widely deployed IDS/IPS platforms. Version 3 is a ground-up C++ rewrite with multithreading, a Lua configuration language, and a modern plugin architecture.

## What Snort 3 Does
- Inspects live network traffic or pcap files for malicious patterns and protocol anomalies
- Matches packets against a database of community and commercial rule sets (Snort rules)
- Operates in IDS mode (passive detection) or IPS mode (inline blocking)
- Reassembles TCP streams and decodes application-layer protocols (HTTP, DNS, SMB, etc.)
- Logs alerts in multiple formats including JSON, syslog, and unified2

## Architecture Overview
Snort 3 uses a pipeline architecture: packet acquisition (DAQ) feeds raw packets into decoders, which normalize protocols and hand off to the detection engine. The detection engine evaluates rules using a multi-pattern matcher (hyperscan or AC-full) against the reassembled stream. Inspectors are protocol-specific plugins that decode HTTP headers, extract file data, or track application state. The entire pipeline is multithreaded, with each packet thread processing independently.

## Self-Hosting & Configuration
- Configuration uses a Lua script (snort.lua) instead of the legacy conf format
- Install community rules from snort.org or use Cisco Talos subscription rules
- Deploy inline using the DAQ afpacket or NFQ module for IPS (blocking) mode
- Tune performance with the max-threads setting and pin threads to CPU cores
- Output alerts to JSON for consumption by SIEMs like Elasticsearch or Splunk

## Key Features
- Multithreaded packet processing for line-rate inspection on multi-core systems
- Lua-based configuration and rule scripting for dynamic detection logic
- Hyperscan regex engine integration for high-speed pattern matching
- File identification and extraction for malware analysis and policy enforcement
- Plugin architecture for custom inspectors, loggers, and IPS actions

## Comparison with Similar Tools
- **Suricata** — multi-threaded IDS/IPS with EVE JSON logging; Snort 3 adds Lua scripting and the Talos rule ecosystem
- **Zeek (Bro)** — network analysis framework focused on logging and scripting; Snort focuses on signature-based alerting
- **OSSEC/Wazuh** — host-based IDS; Snort operates at the network level inspecting packets on the wire
- **Falco** — cloud-native runtime security for containers; Snort inspects traditional network traffic

## FAQ
**Q: What is the difference between Snort 2 and Snort 3?**
A: Snort 3 is a full C++ rewrite with multithreading, Lua configuration, a plugin architecture, and improved protocol inspection. Snort 2 rules are largely compatible.

**Q: Can I use Snort as an IPS?**
A: Yes. Deploy it inline using the NFQ or afpacket DAQ module, and configure rules with drop, reject, or rewrite actions.

**Q: Where do I get rules?**
A: Snort.org provides free community rules. Cisco Talos offers a registered (free, 30-day delay) and a subscriber (real-time) rule set.

**Q: Does Snort 3 support hardware offload?**
A: Yes. It integrates with DPDK for high-speed packet capture and hyperscan for hardware-accelerated regex matching on supported CPUs.

## Sources
- https://github.com/snort3/snort3
- https://www.snort.org/snort3

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Source: https://tokrepo.com/en/workflows/asset-8e2ee290
Author: Script Depot