cis-gcp-cos-2-1-3

name	cis-gcp-cos-2.1.3
description	Ensure NFS and RPC are not enabled
category	cis-gcp-cos
version	1.2.0
author	cyberstrike-official
tags	["cis","gcp","container-optimized-os","nfs","rpc","services"]
cis_id	2.1.3
cis_benchmark	CIS Google Container-Optimized OS Benchmark v1.2.0
tech_stack	["gcp","linux"]
cwe_ids	[]
chains_with	[]
prerequisites	[]
severity_boost	{}

2.1.3 Ensure NFS and RPC are not enabled (Automated)

Description

The Network File System (NFS) is one of the first and most widely distributed file systems in the UNIX environment. It provides the ability for systems to mount file systems of other servers through the network.

Rationale

If the system does not export NFS shares or act as an NFS client, it is recommended that these services be disabled to reduce the remote attack surface.

Audit Procedure

Run the following commands to verify the nfs-server and rpcbind are not enabled:

# systemctl is-enabled nfs-server

disabled
# systemctl is-enabled rpcbind

disabled

Verify result is not "enabled" for both.

Expected Result

Both commands should return disabled, confirming that NFS and RPC services are not enabled.

Remediation

Run the following commands to disable the nfs-server and rpcbind:

# systemctl --now disable nfs-server
# systemctl --now disable rpcbind

/etc is stateless on Container-Optimized OS. Therefore, the steps mentioned above needs to be performed after every boot.

Additional Information:

Additional methods of disabling a service exist. Consult your distribution documentation for appropriate methods.

CIS Controls

Controls Version	Control	IG 1	IG 2	IG 3
v8	4.4 Implement and Manage a Firewall on Servers - Implement and manage a firewall on servers, where supported. Example implementations include a virtual firewall, operating system firewall, or a third-party firewall agent.	X	X	X
v8	4.5 Implement and Manage a Firewall on End-User Devices - Implement and manage a host-based firewall or port-filtering tool on end-user devices, with a default-deny rule that drops all traffic except those services and ports that are explicitly allowed.	X	X	X
v8	4.8 Uninstall or Disable Unnecessary Services on Enterprise Assets and Software - Uninstall or disable unnecessary services on enterprise assets and software, such as an unused file sharing service, web application module, or service function.