Using AWS managed rule groups in AWS Network Firewall
Managed rule groups are collections of predefined, ready-to-use rules that AWS writes and maintains for you. AWS managed rule groups are available for free to Network Firewall customers.
Automatic updates
Keeping up to date on the constantly changing threat landscape can be time consuming and expensive. Managed rule groups can save you time when you implement and use Network Firewall. AWS automatically updates managed rule groups when new vulnerabilities and threats emerge. AWS updates managed rule groups once a day to once a week.
In some cases, AWS is notified of new vulnerabilities before public disclosure due to its participation in a number of private disclosure communities. In those cases, AWS Network Firewall can update rule groups and deploy them to your environment before a new threat is widely known.