Tunnel entry and exit points must be in a deny-by-default security posture.

From Perimeter Router Security Technical Implementation Guide Cisco

Associated with IA controls: ECSC-1

SV-20240r2_rule Tunnel entry and exit points must be in a deny-by-default security posture.

Vulnerability discussion

Having tunnels in a permit any any posture allow traffic to enter and exit the enclave without control from the Information Assurance team or SA.

Check content

Follow the procedures defined in NET-TUNL-002 to determine all tunnel entry and exit points, then ensure each end-point is in a deny by default posture inbound and outbound.

Fix text

Apply a deny by default posture on every tunnel end-point.

Pro Tips

Lavender hyperlinks in small type off to the right (of CSS class id, if you view the page source) point to globally unique URIs for each document and item. Copy the link location and paste anywhere you need to talk unambiguously about these things.

You can obtain data about documents and items in other formats. Simply provide an HTTP header Accept: text/turtle or Accept: application/rdf+xml.