Check your AWS Network Access Control Lists (NACLs) for inbound rules that allow traffic from all ports and limit access to the required ports or port ranges only in order to implement the principle of least privilege and reduce the possibility of unauthorized access at the subnet level.
This rule can help you with the following compliance standards:
This rule can help you work with the AWS Well-Architected Framework
This rule resolution is part of the Cloud Conformity Security & Compliance tool for AWS
Regulating the subnets inbound/ingress traffic by opening just the ports required by your applications will add an additional layer of security to your VPC and protect against malicious activity such as such as Denial of Service (DoS) attacks or Distributed Denial of Service (DDoS) attacks.
To determine if your Amazon Network ACLs allow inbound traffic from all ports, perform the following:
To update your AWS NACL inbound rules configuration in order to allow traffic from specific source port or source port range only, perform the following: