2.1.4 Ensure dns server services are not in use

Information

The Domain Name System (DNS) is a hierarchical naming system that maps names to IP addresses for computers, services and other resources connected to a network.

Unless a system is specifically designated to act as a DNS server, it is recommended that the package be deleted to reduce the potential attack surface.

Solution

Run the following commands to stop bind9.service and remove the bind9 package:

# systemctl stop bind9.service
# apt purge bind9

- OR -

- IF - the bind9 package is required as a dependency:

Run the following commands to stop and mask bind9.service :

# systemctl stop bind9.service
# systemctl mask bind9.service

Impact:

There may be packages that are dependent on the bind9 package. If the bind9 package is removed, these dependent packages will be removed as well. Before removing the bind9 package, review any dependent packages to determine if they are required on the system.

- IF - a dependent package is required: stop and mask the bind9.service leaving the bind9 package installed.

See Also

https://workbench.cisecurity.org/benchmarks/17045

Item Details

Category: CONFIGURATION MANAGEMENT

References: 800-53|CM-6, 800-53|CM-7, CSCv7|9.2

Plugin: Unix

Control ID: 735752d7c354c8e05c89732fea9e7b5db341f905d89283ae3fb5ea25e481db23