ModSecurity vs Qualys Web Application Scanning

ModSecurity is an open-source web application firewall that examines incoming HTTP(S) traffic and can block malicious requests before they reach an application. It runs inside Apache, Nginx or IIS as a module, not as a separate appliance or proxy. The project provides traffic visibility, a rules language and an API for implementing protections. ModSecurity can run alone or with the OWASP Core Rule Set, which the FAQ says provides broad coverage against common web attacks. Listed uses include real-time security monitoring and access control, HTTP traffic logging, passive security assessment and web application hardening. It supports Linux, Unix-like systems, Windows and macOS when paired with a compatible web server. Installation guidance recommends starting in detection-only mode, reviewing and tuning events, then enabling blocking. Inspecting every request can have a small performance impact, and tuning rules can help manage it. OWASP maintains the project with community contributors, with Slack and GitHub listed for community activity. The plan costs nothing; managed rule sets are not included.

Qualys Web Application Scanning has no write-up on Specifiction yet; its figures are above.