IDS/IPS

Popular open source IDS/IPS

Popular open source Intrusion Detection Systems/Intrusion Prevention Systems (IDS/IPS) ordered by relative popularity:

Suricata

• Type: High-performance NIDS/NIPS

• Features:

  • Multi-threaded, supports HTTP/2, TLS, and file extraction.

  • EVE JSON logs for easy SIEM integration.

  • Supports Lua scripting for advanced detection.

• Use Case: Enterprise networks, high-speed traffic analysis.

• Website: https://suricata.io/

Snort

• Type: Signature-based NIDS/NIPS

• Features:

  • Lightweight, rule-based detection.

  • Large community rule sets (Emerging Threats, Talos).

  • Can be used inline (IPS mode).

• Use Case: Small to medium networks, basic threat detection.

• Website: https://www.snort.org/

Wazuh

• Type: HIDS + SIEM (Fork of OSSEC with extended features)

• Features:

  • Combines HIDS, log analysis, file integrity monitoring, and vulnerability detection.

  • Integrates with Elasticsearch for visualization.

• Use Case: Endpoint security, compliance (PCI DSS, GDPR), and threat detection.

• Website: https://wazuh.com/

OSSEC

• Type: Host-based IDS (HIDS)

• Features:

  • Monitors file integrity, log analysis, rootkit detection, and active responses.

  • Can be used as a centralized log analysis tool.

• Use Case: Server security, compliance monitoring, and log-based intrusion detection.

• Website: https://www.ossec.net/

Fail2Ban

• Type: Lightweight IPS (for log-based blocking)

• Features:

  • Scans log files (e.g., SSH, Apache) and bans malicious IPs.

  • Uses iptables/nftables for blocking.

• Use Case: Protecting servers from brute-force attacks.

• Website: https://www.fail2ban.org/

Zeek (formerly Bro)

• Type: Network Analysis Framework (NIDS)

• Features:

  • Focuses on network traffic analysis rather than signature-based detection.

  • Generates detailed logs for protocols, files, and connections.

  • Highly customizable with scripting (Bro scripting language).

• Use Case: Best for network monitoring, forensics, and anomaly detection (deep traffic analysis).

• Website: https://zeek.org/

Security Onion

• Type: Network Security Monitoring (NSM) Suite (includes Suricata, Zeek, and other tools)

• Features:

  • Combines Suricata (IDS/IPS), Zeek (network analysis), and Elastic Stack (log analysis).

  • Provides a full SIEM-like environment for threat detection.

• Use Case: Enterprise-grade network security monitoring.

• Website: https://securityonion.net/

AIDE (Advanced Intrusion Detection Environment)

• Type: File Integrity Checker (HIDS)

• Features:

  • Creates a database of file hashes and detects unauthorized changes.

• Use Case: Server security & compliance auditing.

• Website: http://aide.sourceforge.net/

Samhain

• Type: HIDS (File integrity, log monitoring)

• Features:

  • Monitors file changes, rootkits, and suspicious processes.

  • Supports centralized logging and stealth operation.

• Use Case: Server integrity monitoring.

• Website: https://www.la-samhna.de/samhain/

OpenWIPS-NG

• Type: Wireless IPS (WIPS)

• Features:

  • Detects and prevents Wi-Fi attacks (rogue APs, deauth attacks).

  • Works with RF sensors for wireless monitoring.

• Use Case: Wireless network security.

• Website: https://openwips-ng.org/

Summary Table

Tool	Type	Best For
Suricata	High-performance NIDS/NIPS	High-speed networks, modern threats
Snort	Signature-based NIDS/NIPS	Small/medium networks, legacy setups
Wazuh	HIDS + SIEM	Endpoint security, compliance
OSSEC	HIDS	Log analysis, file integrity monitoring
Fail2Ban	Lightweight IPS	Brute-force protection
Zeek (Bro)	NIDS (Traffic Analysis)	Network forensics, anomaly detection
Security Onion	NSM Suite	Full network monitoring (Suricata + Zeek)
AIDE	File Integrity	Server security auditing
Samhain	HIDS	Stealth monitoring, rootkit detection
OpenWIPS-NG	Wireless IPS	Wi-Fi security

Snort vs. Suricata

Feature	Snort	Suricata
Detection Type	Signature-based NIDS/NIPS	Signature + anomaly-based NIDS/NIPS
Performance	Single-threaded	Multi-threaded (scales better)
Rule Sources	Talos, Emerging Threats (ET)	ET Open, ET Pro, custom Lua rules
IPS Mode	Yes (inline via afpacket/nfq)	Yes (inline via nfqueue)
Protocol Support	Basic (HTTP, DNS, etc.)	Advanced (HTTP/2, TLS, QUIC)
File Extraction	Limited (via preprocessors)	Built-in (PCAP, files, TLS logs)
Logging Format	Plaintext, unified2 binary	EVE JSON (SIEM-friendly)
Scripting	Limited (preprocessors in C)	Lua scripting for advanced rules
Hardware Usage	Lower RAM/CPU	Higher RAM (due to multithreading)
Best For	Small/medium networks, legacy setups	High-speed networks, modern threats

Key Takeaways

• Snort is simpler, lightweight, and ideal for smaller deployments.

• Suricata is more scalable, with modern protocol support and better SIEM integration.

• Both support inline IPS mode, but Suricata handles encrypted traffic (TLS) better.