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V-281355

CAT II (Medium)

RHEL 10 must ignore IPv6 Internet Control Message Protocol (ICMP) redirect messages.

Rule ID

SV-281355r1167215_rule

STIG

Red Hat Enterprise Linux 10 Security Technical Implementation Guide

Version

V1R1

CCIs

CCI-002385 CCI-001110

Discussion

An illicit ICMP redirect message could result in a man-in-the-middle attack. Satisfies: SRG-OS-000420-GPOS-00186, SRG-OS-000142-GPOS-00086

Check Content

Note: If IPv6 is disabled on the system, this requirement is not applicable.

Verify RHEL 10 ignores IPv6 ICMP redirect messages.

Check the value of the "net.ipv6.conf.all.accept_redirects" variable with the following command:

$ sysctl net.ipv6.conf.all.accept_redirects
net.ipv6.conf.all.accept_redirects = 0

If "net.ipv6.conf.all.accept_redirects" is not set to "0" or is missing, this is a finding.

Fix Text

Configure RHEL 10 to ignore Internet Protocol version 6 (IPv6) ICMP redirect messages.

Create a configuration file if it does not already exist:

$ sudo vi /etc/sysctl.d/ipv6_accept_redirects.conf

Add the following line to the file:

net.ipv6.conf.all.accept_redirects = 0

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

$ sudo sysctl --system