Control: 5.3 Ensure no security groups allow ingress from 0.0.0.0/0 to remote server administration ports

Description

Security groups provide stateful filtering of ingress and egress network traffic to AWS resources. It is recommended that no security group allows unrestricted ingress access to remote server administration ports, such as SSH on port 22 and RDP on port 3389, using either the TCP (6), UDP (17), or ALL (-1) protocols.

Public access to remote server administration ports, such as 22 (when used for SSH, not SFTP) and 3389, increases the attack surface of resources and unnecessarily raises the risk of resource compromise.

Remediation

Perform the following to implement the prescribed state:

1. Login to the AWS VPC Console at https://console.aws.amazon.com/vpc/home.
2. In the left pane, click Security Groups.
3. For each security group, perform the following:

• Select the security group.
• Click the Inbound Rules tab.
• Click the Edit inbound rules button.
• Identify the rules to be edited or removed.
• 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 rules.