Check your Amazon VPC 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 (POLP) and reduce the possibility of unauthorized access at the subnet level.
This rule can help you with the following compliance standards:
- PCI
- APRA
- MAS
- NIST4
For further details on compliance standards supported by Conformity, see here.
This rule can help you work with the AWS Well-Architected Framework.
This rule resolution is part of the Conformity Security & Compliance tool for AWS.
Regulating the VPC subnets inbound/ingress traffic by opening just the ports required by your applications, will add an additional layer of security to your VPC network and protect against malicious activities such as such as Denial of Service (DoS) and Distributed Denial of Service (DDoS) attacks.
Audit
To determine if your Network ACLs (NACLs) allow inbound traffic from all ports, perform the following operations:
Remediation / Resolution
To reconfigure your Network ACL inbound rules in order to allow traffic from specific source port or source port range only, perform the following operations:
References
- AWS Documentation
- Internetwork traffic privacy in Amazon VPC
- Control traffic to subnets using Network ACLs
- What is Amazon VPC?
- AWS Command Line Interface (CLI) Documentation
- ec2
- describe-network-acls
- replace-network-acl-entry
- create-network-acl-entry
- CloudFormation Documentation
- AWS::EC2::VPC
- Terraform Documentation
- AWS Provider