2.2.3 Ensure dhcp server services are not in use

Information

The Dynamic Host Configuration Protocol (DHCP) is a service that allows machines to be dynamically assigned IP addresses. There are two versions of the DHCP protocol DHCPv4 and DHCPv6 . At startup the server may be started for one or the other via the -4 or -6 arguments.

Unless a system is specifically set up to act as a DHCP server, it is recommended that the dhcp-server package be removed to reduce the potential attack surface.

Solution

Run the following commands to stop dhcpd.service and dhcpd6.service and remove dhcp package:

# systemctl stop dhcpd.service dhcpd6.service
# yum remove dhcp

-OR-

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

Run the following commands to stop and mask dhcpd.service and dhcpd6.service :

# systemctl stop dhcpd.service dhcpd6.service
# systemctl mask dhcpd.service dhcpd6.service

Impact:

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

-IF- a dependent package is required: stop and mask the dhcpd.service and dhcpd6.service leaving the dhcp-server package installed.

See Also

https://workbench.cisecurity.org/benchmarks/15964

Item Details

Category: CONFIGURATION MANAGEMENT

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

Plugin: Unix

Control ID: df63a95ca824f20c816b16aac06ba4ac5a9f454d9eb48a6ba10b5f8067286fdf