STIGQter STIGQter: STIG Summary: Red Hat Enterprise Linux 8 Security Technical Implementation Guide Version: 2 Release: 8 Benchmark Date: 01 Jul 2026:

RHEL 8 must not forward IPv6 source-routed packets by default.

DISA Rule

SV-230539r1017301_rule

Vulnerability Number

V-230539

Group Title

SRG-OS-000480-GPOS-00227

Rule Version

RHEL-08-040250

Severity

CAT II

CCI(s)

Weight

10

Fix Recommendation

Configure RHEL 8 to not forward IPv6 source-routed packets by default.

Add or edit the following line in a system configuration file, in the "/etc/sysctl.d/" directory:

net.ipv6.conf.default.accept_source_route=0

Remove any configurations that conflict with the above from the following locations:
/run/sysctl.d/*.conf
/usr/local/lib/sysctl.d/*.conf
/usr/lib/sysctl.d/*.conf
/lib/sysctl.d/*.conf
/etc/sysctl.conf
/etc/sysctl.d/*.conf

Load settings from all system configuration files with the following command:

$ sudo sysctl --system

Check Contents

Verify RHEL 8 does not accept IPv6 source-routed packets by default.

Note: If IPv6 is disabled on the system, this requirement is Not Applicable.

Check the value of the accept source route variable with the following command:

$ sudo sysctl net.ipv6.conf.default.accept_source_route

net.ipv6.conf.default.accept_source_route = 0

If the returned line does not have a value of "0", a line is not returned, or the line is commented out, this is a finding.

Check that the configuration files are present to enable this network parameter.

$ sudo grep -r net.ipv6.conf.default.accept_source_route /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf

/etc/sysctl.d/99-sysctl.conf: net.ipv6.conf.default.accept_source_route = 0

If "net.ipv6.conf.default.accept_source_route" is not set to "0", is missing or commented out, this is a finding.

If conflicting results are returned, this is a finding.

Vulnerability Number

V-230539

Documentable

False

Rule Version

RHEL-08-040250

Severity Override Guidance

Verify RHEL 8 does not accept IPv6 source-routed packets by default.

Note: If IPv6 is disabled on the system, this requirement is Not Applicable.

Check the value of the accept source route variable with the following command:

$ sudo sysctl net.ipv6.conf.default.accept_source_route

net.ipv6.conf.default.accept_source_route = 0

If the returned line does not have a value of "0", a line is not returned, or the line is commented out, this is a finding.

Check that the configuration files are present to enable this network parameter.

$ sudo grep -r net.ipv6.conf.default.accept_source_route /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf

/etc/sysctl.d/99-sysctl.conf: net.ipv6.conf.default.accept_source_route = 0

If "net.ipv6.conf.default.accept_source_route" is not set to "0", is missing or commented out, this is a finding.

If conflicting results are returned, this is a finding.

Check Content Reference

M

Target Key

2921