cis-ubuntu2004-v300-2-1-9

name	cis-ubuntu2004-v300-2-1-9
description	Ensure network file system services are not in use
category	cis-networking
version	3.0.0
author	cyberstrike-official
tags	["cis","ubuntu","linux","ubuntu-20.04","services"]
cis_id	2.1.9
cis_benchmark	CIS Ubuntu Linux 20.04 LTS Benchmark v3.0.0
tech_stack	["ubuntu","linux"]
cwe_ids	[]
chains_with	[]
prerequisites	[]
severity_boost	{}

2.1.9 Ensure network file system services are not in use (Automated)

Profile

• Level 1 - Server
• Level 1 - Workstation

Description

The Network File System (NFS) is one of the first and most widely distributed file systems in the client/server model. It allows remote hosts to mount file systems over a network and interact with those file systems as though they are mounted locally. If the system does not export NFS shares, it is recommended that the NFS be disabled to reduce the remote attack surface.

Rationale

If the system does not export NFS shares or act as an NFS server, it is recommended that the nfs-server service be disabled to reduce the remote attack surface.

Audit Procedure

Command Line

Run the following command to verify nfs-kernel-server is not installed:

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

If installed, run:

# systemctl is-enabled nfs-server.service
# systemctl is-active nfs-server.service

Verify the service is not enabled and not active.

Expected Result

nfs-kernel-server should not be installed, or if installed, the service should be stopped and masked.

Remediation

Command Line

Run the following commands to stop, mask, and purge nfs-kernel-server:

# systemctl stop nfs-server.service
# systemctl mask nfs-server.service
# apt purge nfs-kernel-server

Default Value

nfs-kernel-server is not installed by default.

References

1. NIST SP 800-53 Rev. 5: CM-6, 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: T1005, T1039, T1083, T1135, T1210 | TA0008 | M1042