ModSecurity

Cloudflare

cloudflare.com

Popular

Global edge network for CDN, DNS, DDoS protection, WAF, Zero Trust and the Workers developer platform.

OWASP CRS

coreruleset/coreruleset

Popular

Generic attack-detection rule set (SQLi, XSS, RCE) used by ModSecurity, Coraza and many cloud WAFs.

CrowdSec

crowdsecurity/crowdsec

Rising

Collaborative IPS that parses logs, blocks attackers and shares IP reputation across its user network.

Coraza

corazawaf/coraza

Rising

OWASP Go WAF engine compatible with ModSecurity rules and CRS; embeds in Caddy, Envoy and Go apps.

SafeLine

chaitin/SafeLine

Trending

Self-hosted WAF and reverse proxy from Chaitin with semantic attack detection and bot challenges.

Anubis

TecharoHQ/anubis

Trending

Proof-of-work challenge proxy that shields websites from aggressive AI scrapers and bots.

Fail2ban

fail2ban/fail2ban

Popular

Bans IPs showing malicious behavior, such as SSH brute force, by watching log files.

Wazuh

wazuh/wazuh

Popular

Open-source XDR and SIEM with host agents for intrusion detection, file integrity and compliance.

Suricata

OISF/suricata

Popular

High-performance network IDS/IPS and security monitoring engine from the OISF.