What it does
ModSecurity is an open-source web application firewall engine with HTTP-traffic visibility and a rule language for application-defense policies.
ModSecurity is a WAF engine to pair with a suitable web-server connector and rules, including the OWASP Core Rule Set. Choose where requests reach the engine and examine matches on legitimate traffic before enforcing blocks. The project explicitly lists full HTTP traffic logging as a use case. Treat those operator-controlled logs as potentially sensitive request data and define access, redaction and retention for the deployment. A WAF adds request inspection; application vulnerabilities still need repair.
Strengths
- Rules-based HTTP inspection and monitoring
Best for
- Administrators adding a managed WAF layer to applications
Sources
- ModSecurity Project – Open-Source Web Application Firewall (Oct 26, 2026)
- ModSecurity v3 LICENSE (Oct 26, 2026)