Ensure Network firewall have subnet change protection enabled

The network firewall helps you protect your VPC. Set subnet change protection to protect against accidental modification of the subnet associations, which might expose a protected subnet.

Risk Level: High
Cloud Entity: AWS Network-Firewall
CloudGuard Rule ID: D9.AWS.NET.63
Covered by Spectral: Yes
Category: Networking & Content Delivery


NetworkFirewall should have subnetChangeProtection=true


From Portal

  1. Sign in to the AWS console
  2. In the console, select the specific region
  3. Navigate to the 'AWS Network Firewall' service.
  4. In the left pane under 'Network Firewall' click on Firewall.
  5. Select desired firewall and click on 'Firewall details'.
  6. Go to 'change protection' and click on 'Edit'.
  7. Choose 'enable' for Subnet change protection option and click 'save'.

From TF

resource "aws_networkfirewall_firewall" "example" {
	- subnet_change_protection = false
	+ subnet_change_protection = true

From Command Line
In order to set Subnet change protection to TRUE, use to following CLI command:

aws network-firewall update-subnet-change-protection --firewall-arn FW_ARN --subnet-change-protection

Note: The flag --subnet-change-protection will set the subnet change protection to TRUE.


  1. https://docs.aws.amazon.com/network-firewall/latest/APIReference/API_UpdateSubnetChangeProtection.html
  2. CLI: https://awscli.amazonaws.com/v2/documentation/api/latest/reference/network-firewall/update-subnet-change-protection.html

AWS Network-Firewall

AWS Network Firewall is a managed service that makes it easy to deploy essential network protections for all of your Amazon Virtual Private Clouds (VPCs).AWS Network Firewall���s flexible rules engine lets you define firewall rules that give you fine-grained control over network traffic, such as blocking outbound Server Message Block (SMB) requests to prevent the spread of malicious act

Compliance Frameworks

  • AWS CIS Controls V 8
  • AWS CloudGuard Best Practices
  • AWS CloudGuard SOC2 based on AICPA TSC 2017
  • AWS HITRUST v11.0.0
  • AWS ISO27001:2022
  • AWS ITSG-33
  • AWS MITRE ATT&CK Framework v10
  • AWS MITRE ATT&CK Framework v11.3
  • AWS NIST 800-53 Rev 5
  • CloudGuard AWS All Rules Ruleset