Cis Ubuntu1804 V220 3 3 11

CIS Ubuntu Linux 18.04 LTS Benchmark v2.2.0 - Control 3.3.11

Description

This setting disables the system's ability to accept IPv6 router advertisements.

Rationale

It is recommended that systems do 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.

Impact

None.

Audit Procedure

Command Line

Run the following commands to verify IPv6 router advertisements are not accepted:

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

grep -E '^\s*net\.ipv6\.conf\.(all|default)\.accept_ra\s*=\s*0\b' /etc/sysctl.conf /etc/sysctl.d/*.conf

Expected Result

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

Remediation

Command Line

Set the following parameters in /etc/sysctl.conf or a /etc/sysctl.d/* file:

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

Run the following commands to set the active kernel parameters:

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

Default Value

net.ipv6.conf.all.accept_ra = 1, net.ipv6.conf.default.accept_ra = 1

References

1. NIST SP 800-53 Rev. 5: CM-7, SC-5, SC-7
2. CIS Ubuntu Linux 18.04 LTS Benchmark v2.2.0

CIS Controls

Version 8

4.1 Establish and Maintain a Secure Configuration Process - Establish and maintain a secure configuration process for enterprise assets.

Version 7

5.1 Establish Secure Configurations - Maintain documented, standard security configuration standards for all authorized operating systems and software.

Profile Applicability

• Level 1 - Server
• Level 1 - Workstation

Assessment Status

Automated