ModSecurity is an open-source web application firewall and security engine. It functions as an HTTP traffic inspector and intrusion detection system that filters incoming web requests and responses against a set of security rules to block threats and prevent attacks on web servers.
The project provides a modular framework for implementing restrictive security policies and custom filtering logic. It identifies and blocks common injection attacks, such as cross-site scripting and SQL injection, while hardening web applications to reduce their overall attack surface.
Its broader capabilities include web traffic auditing, the ability to process XML content, and the identification of user location through database lookups. It also supports the execution of custom scripts to implement dynamic security behavior during request processing.
