MySQL 8.4 Reference Manual Including MySQL NDB Cluster 8.4
MySQL Server includes a plugin library that enables administrators to introduce an increasing delay in server response to connection attempts after a configurable number of consecutive failed attempts. This capability provides a deterrent that slows down brute force attacks against MySQL user accounts. The plugin library contains two plugins:
          CONNECTION_CONTROL checks incoming
          connection attempts and adds a delay to server responses as
          necessary. This plugin also exposes system variables that
          enable its operation to be configured and a status variable
          that provides rudimentary monitoring information.
        
          The CONNECTION_CONTROL plugin uses the
          audit plugin interface (see
          Writing Audit Plugins). To collect
          information, it subscribes to the
          MYSQL_AUDIT_CONNECTION_CLASSMASK event
          class, and processes
          MYSQL_AUDIT_CONNECTION_CONNECT and
          MYSQL_AUDIT_CONNECTION_CHANGE_USER
          subevents to check whether the server should introduce a delay
          before responding to connection attempts.
        
          CONNECTION_CONTROL_FAILED_LOGIN_ATTEMPTS
          implements an INFORMATION_SCHEMA table that
          exposes more detailed monitoring information for failed
          connection attempts. For more information about this table,
          see
          Section 28.6.2, “The INFORMATION_SCHEMA CONNECTION_CONTROL_FAILED_LOGIN_ATTEMPTS Table”.
        
The following sections provide information about connection control plugin installation and configuration.