UCF STIG Viewer Logo
Changes are coming to https://stigviewer.com. Take our survey to help us understand your usage and how we can better serve you in the future.
Take Survey

The SUSE operating system must not allow interfaces to accept Internet Protocol version 4 (IPv4) Internet Control Message Protocol (ICMP) redirect messages by default.


Overview

Finding ID Version Rule ID IA Controls Severity
V-235019 SLES-15-040340 SV-235019r622137_rule Medium
Description
ICMP redirect messages are used by routers to inform hosts that a more direct route exists for a particular destination. These messages modify the host's route table and are unauthenticated. An illicit ICMP redirect message could result in a man-in-the-middle attack.
STIG Date
SUSE Linux Enterprise Server 15 Security Technical Implementation Guide 2021-11-30

Details

Check Text ( C-38207r619326_chk )
Verify the SUSE operating system does not accept IPv4 ICMP redirect messages by default.

Check the value of the default IPv4 accept_redirects variable with the following command:

> sudo sysctl net.ipv4.conf.default.accept_redirects
net.ipv4.conf.default.accept_redirects = 0

If the network parameter "ipv4.conf.default.accept_redirects" is not equal to "0" or nothing is returned, this is a finding.
Fix Text (F-38170r619327_fix)
Configure the SUSE operating system to not accept IPv4 ICMP redirect messages by default by running the following command as an administrator:

> sudo sysctl -w net.ipv4.conf.default.accept_redirects=0

If "0" is not the system's default value, add or update the following line in "/etc/sysctl.d/99-stig.conf":

> sudo sh -c 'echo "net.ipv4.conf.default.accept_redirects=0" >> /etc/sysctl.d/99-stig.conf'

> sudo sysctl --system