The Photon operating system must disable systemd fallback Domain Name System (DNS).
An XCCDF Rule
Description
Systemd contains an ability to set fallback DNS servers. This is used for DNS lookups in the event no system-level DNS servers are configured or other DNS servers are specified in the systemd "resolved.conf" file. If uncommented, this configuration contains Google DNS servers by default and could result in DNS leaking information unknowingly in the event DNS is absent or misconfigured at the system level.
- ID
- SV-256590r991589_rule
- Version
- PHTN-30-000245
- Severity
- Medium
- References
- Updated
Remediation Templates
A Manual Procedure
Navigate to and open:
/etc/systemd/resolved.conf
Add or update the "FallbackDNS" entry to the following: