The ALG must fail securely in the event of an operational failure.

Severity	Group ID	Group Title	Version	Rule ID	Date	STIG Version
medium	V-205009	SRG-NET-000365	SRG-NET-000365-ALG-000123	SV-205009r396402_rule	2024-12-04	2

Description
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.

Description

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.

ℹ️ Check
Verify the ALG fails securely in the event of an operational failure. If the ALG does not fail securely in the event of an operational failure, this is a finding.

✔️ Fix
Configure the ALG to fail securely in the event of an operational failure.