V-285283

Discussion

Authoritative name servers (especially primary name servers) should be configured with an allow-transfer access control substatement designating the list of hosts from which zone transfer requests can be accepted. These restrictions address the denial-of-service threat and potential exploits from unrestricted dissemination of information about internal resources. Based on the need-to-know, the only name servers that need to refresh their zone files periodically are the secondary name servers. Zone transfer from primary name servers should be restricted to secondary name servers. The zone transfer should be completely disabled in the secondary name servers. The address match list argument for the allow-transfer substatement should consist of IP addresses of secondary name servers and stealth secondary name servers.

Check Content

Verify Infoblox is configured to accept zone transfers to specified external non-Grid DNS servers.

1. Navigate to the Data Management >> DNS >>  Zones tab. 
2. Review each zone by clicking "Edit" icon and inspecting the "DNS service members" tab. Note: If using Name Server Groups, select "Name Servers" tab.
3. Make note of all external DNS service members, those NOT identified as Type "Grid" (Primary or Secondary). 
4. Click the "Zone Transfers" tab. 
5. Verify only the external non-Grid DNS service members identified as DNS service members for the zone or authorized stealth servers are the only systems authorized to perform zone transfers as authorized by a "Named ACL" or "Set of ACEs". 
6. When complete, click "Cancel" to exit the "Properties" screen. 

If Access Controls Lists (ACLs) are not configured for zone transfers to external non-Grid servers, this is a finding.