16 - Restrict Query Origins

Information

BIND can be configured to limit restrict access to its query services. This is made possible by the allow-query option. It is recommended that this option be utilized to restrict access to the server's query services.
It is also recommended that caching-only servers limit all queries to only the expected internal networks by adding ACL's to define the allowed local networks and restrict recursive queries. Note: that localhost and localnets are BIND predefined ACLs, and should not be used for new ACL names.

Rationale:

Using allow-query in conjunction with an ACL of trusted clients will prevent unauthorized access to name services content. Additionally, the exposure of vulnerabilities present in BIND's query handlers is reduced by this configuration as requests originating from untrusted entities will be rejected before the request is fully parsed by named.

Solution

1. Create ACLs for the local networks in named.conf
acl 'local' { 127.0.0.1; };
acl 'mynets' { 10.1.2.0/24; 10.1.3.0/24; 10.1.4.0/24; }; . . .
2. 2. Add the following to the named.conf global options:
options { . . . allow-query { local; mynets; }; . . . }

Item Details

Category: SYSTEM AND COMMUNICATIONS PROTECTION

References: 800-53|SC-20

Plugin: Unix

Control ID: 8076dfac1a1cc1510f7944c4aeb67eeac81c2d570b11529d37373a23f6d19f00