Description:
Security groups provide stateful filtering of ingress/egress network traffic to AWS resources. It is recommended that no security group allows unrestricted ingress access to any port.
Rationale:
Removing unfettered connectivity to remote console services, such as SSH, reduces a server's exposure to risk. Ensure no security groups allow ingress from 0.0.0.0/0 or ::/0 to any port.
Audit:
Perform the following to determine if the account is configured as prescribed:
1. Login to the AWS Management 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:
4. Select the security group
5. Click the Inbound Rules tab
6. Ensure no rule exists that has a port range that includes any port and has a Source of 0.0.0.0/0
Remediation:
Perform the following to implement the prescribed state:
1. Login to the AWS Management 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:
4. Select the security group
5. Click the Inbound Rules tab
6. Identify the rules to be removed
7. Click the x in the Remove column
8. Click Save
Impact:
For updating an existing environment, care should be taken to ensure that administrators currently relying on an existing ingress from 0.0.0.0/0 have access to any port through another security group.
Resource: