Information
The Network Access Control List (NACL) function provide stateless filtering of ingress and egress network traffic to AWS resources. It is recommended that no NACL allows unrestricted ingress access to remote server administration ports, such as SSH to port 22 and RDP to port 3389, using either the TDP (6), UDP (17) or ALL (-1) protocols
Rationale:
Public access to remote server administration ports, such as 22 and 3389, increases resource attack surface and unnecessarily raises the risk of resource compromise.
Solution
From Console:
Perform the following:
Login to the AWS Management Console at https://console.aws.amazon.com/vpc/home
In the left pane, click Network ACLs
For each network ACL to remediate, perform the following:
Select the network ACL
Click the Inbound Rules tab
Click Edit inbound rules
Either A) update the Source field to a range other than 0.0.0.0/0, or, B) Click Delete to remove the offending inbound rule
Click Save