WAF (web application firewall)
A filter in front of a web application that inspects HTTP requests and blocks those that match attack or bot rules. Stricter rule sets catch more attacks and also block more real users by mistake (false positives).
Security
In Quorum#
Web application firewall research unlocks the WAF Component. It blocks a share of bot requests and, by mistake, a share of real users, set by its paranoia level: level 1 blocks 60% of bots and 0.1% of users, level 2 (the default) 80% and 0.5%, level 3 92% and 2%, level 4 98% and 6%. Higher levels cost more CPU per request, up to 4 times level 1. Under attack mode blocks 99% of bots and 1% of users and adds 40 ms.
Read next#
DDoS (distributed denial of service), Credential stuffing, ReDoS (regular expression denial of service), Rate limiting