cis-ubuntu1204-v110-7-3-1

name	cis-ubuntu1204-v110-7-3-1
description	Disable IPv6 Router Advertisements
category	cis-os-hardening
version	1.1.0
author	cyberstrike-official
tags	["cis","ubuntu",12.04,"linux","networking","ipv6","router-advertisements","sysctl"]
cis_id	7.3.1
cis_benchmark	CIS Ubuntu 12.04 LTS Server Benchmark v1.1.0
tech_stack	["ubuntu","linux"]
cwe_ids	[]
chains_with	[]
prerequisites	[]
severity_boost	{}

7.3.1 Disable IPv6 Router Advertisements (Not Scored)

Profile Applicability

• Level 1

Description

This setting disables the systems ability to accept router advertisements.

Rationale

It is recommended that systems not accept router advertisements as they could be tricked into routing traffic to compromised machines. Setting hard routes within the system (usually a single default route to a trusted router) protects the system from bad routes.

Audit Procedure

Using Command Line

Perform the following to determine if the system is disabled from accepting router advertisements:

/sbin/sysctl net.ipv6.conf.all.accept_ra
/sbin/sysctl net.ipv6.conf.default.accept_ra

Expected Result

net.ipv6.conf.all.accept_ra = 0
net.ipv6.conf.default.accept_ra = 0

Remediation

Using Command Line

Set the net.ipv6.conf.all.accept_ra and net.ipv6.conf.default.accept_ra parameter to 0 in /etc/sysctl.conf:

net.ipv6.conf.all.accept_ra=0
net.ipv6.conf.default.accept_ra=0

Modify active kernel parameters to match:

/sbin/sysctl -w net.ipv6.conf.all.accept_ra=0
/sbin/sysctl -w net.ipv6.conf.default.accept_ra=0
/sbin/sysctl -w net.ipv6.route.flush=1

Default Value

IPv6 router advertisements are accepted by default.

References

• CIS Ubuntu 12.04 LTS Server Benchmark v1.1.0

Profile

Level 1 - Not Scored