Free DISA STIG and SRG Library | Vaulted

V-72419

On the BIND 9.x server the platform on which the name server software is hosted must be configured to send outgoing DNS messages from a random port.

Finding ID
BIND-9X-001059
Rule ID
SV-87043r1_rule
Severity
Cat III
CCE
(None)
Group Title
SRG-APP-000516-DNS-000110
CCI
CCI-000366
Target Key
(None)
Documentable
No
Discussion

Hosts that run the name server software should not provide any other services and therefore should be configured to respond to DNS traffic only. Outgoing DNS messages should be sent from a random port to minimize the risk of an attacker's guessing the outgoing message port and sending forged replies.

Fix Text

Edit the "named.conf" file. Configure the BIND 9.x server to only use the "port" flag with the "listen-on" and "listen-on-v6" statements: options { listen-on port 53 { <ip_address>; }; listen-on-v6 port 53 { <ip_v6_address>; }; }; Restart the BIND 9.x process.

Check Content

Verify that the BIND 9.x server does not limit outgoing DNS messages to a specific port. Inspect the "named.conf" file for the any instance of the "port" flag: options { listen-on port 53 { <ip_address>; }; listen-on-v6 port 53 { <ip_v6_address>; }; }; If any "port" flag is found outside of the "listen-on" or "listen-on-v6" statements, this is a finding.