cis-ubuntu2004-v300-2-1-3

DevOps & Security

Ensure dhcp server services are not in use

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Source SKILL.md: https://github.com/CyberStrikeus/CyberStrike/blob/HEAD/.cyberstrike/skill/CIS_benchmarks/Operating_Systems/Ubuntu/CIS_Ubuntu_Linux_20.04_LTS_Benchmark_v3.0.0/cis-ubuntu2004-v300-2-1-3/SKILL.md

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2.1.3 Ensure dhcp server services are not in use (Automated)

Profile

Level 1 - Server
Level 1 - Workstation

Description

Dynamic Host Configuration Protocol (DHCP) is a service that allows machines to be automatically assigned IP addresses, reducing the administration burden of manually assigning IP addresses to all devices on a network.

Rationale

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

Audit Procedure

Command Line

Run the following command to verify isc-dhcp-server is not installed:

# dpkg-query -W -f='${binary:Package}\t${Status}\t${db:Status-Status}\n' isc-dhcp-server

If installed, run:

# systemctl is-enabled isc-dhcp-server.service isc-dhcp-server6.service
# systemctl is-active isc-dhcp-server.service isc-dhcp-server6.service

Verify the services are not enabled and not active.

Expected Result

isc-dhcp-server should not be installed, or if installed, the services should be stopped and masked.

Remediation

Command Line

Run the following commands to stop, mask, and purge isc-dhcp-server:

# systemctl stop isc-dhcp-server.service isc-dhcp-server6.service
# systemctl mask isc-dhcp-server.service isc-dhcp-server6.service
# apt purge isc-dhcp-server

Default Value

isc-dhcp-server is not installed by default.

References

http://www.isc.org/software/dhcp
NIST SP 800-53 Rev. 5: CM-7

CIS Controls

Controls Version	Control	IG 1	IG 2	IG 3
v8	4.8 Uninstall or Disable Unnecessary Services on Enterprise Assets and Software		x	x
v7	9.2 Ensure Only Approved Ports, Protocols and Services Are Running		x	x

MITRE ATT&CK Mappings: T1203, T1210, T1543, T1543.002 | TA0008 | M1042