The layer 2 switch must fail securely in the event of an operational failure of a boundary protection device.

If a boundary protection device fails in an unsecure manner (open), information external to the boundary protection device may enter, or the device may permit unauthorized information release.

Secure failure ensures when a boundary control device fails, all traffic will be subsequently denied.

Fail secure is a condition achieved by employing information system mechanisms to ensure in the event of operational failures of boundary protection devices at managed interfaces (e.g., routers, firewalls, guards, and application gateways residing on protected subnetworks commonly referred to as demilitarized zones), information systems do not enter into unsecure states where intended security properties no longer hold.

This requirement also applies to Zero Trust initiatives.

Verify the layer 2 switch fails securely in the event of an operational failure of a boundary protection device.

If the layer 2 switch does not fail securely in the event of an operational failure of a boundary protection device, this is a finding.

Configure the layer 2 switch to fail securely in the event of an operational failure of a boundary protection device.