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

Severity	Group ID	Group Title	Version	Rule ID	Date	STIG Version
medium	V-279222	SRG-NET-000365-ALG-000123	SYME-00-010200	SV-279222r1170676_rule	2025-12-16	1

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
1. Log in to the Integrated Secure Gateway (ISG) SSH CLI. 2. Enter "enable" and "configure terminal". 3. Enter "bridge view". If the mode for the bridge in use does not state "fail-closed", this is a finding.

✔️ Fix
1. Log in to the Integrated Secure Gateway (ISG) SSH CLI. 2. Enter "enable" and "configure terminal". 3. Enter "bridge view". 4. Find the bridge in use for the Edge SWG, e.g., "passthru-2:0". 5. Enter "bridge edit passthru-2:0 mode fail-closed".