The SUSE operating system must prevent Internet Protocol version 4 (IPv4) Internet Control Message Protocol (ICMP) redirect messages from being accepted.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
| V-217291 | SLES-12-030390 | SV-217291r991589_rule | CCI-000366 | 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 12 Security Technical Implementation Guide | 2025-05-14 | |||
Details
Check Text (C-217291r991589_chk)
Verify the SUSE operating system does not accept ICMP redirect messages.
Check the value of the "net.ipv4.conf.all.accept_redirects" variable with the following command:
# sysctl net.ipv4.conf.all.accept_redirects
net.ipv4.conf.all.accept_redirects =0
If the returned line does not have a value of "0" this is a finding.
Fix Text (F-18517r370030_fix)
Configure the SUSE operating system to the required kernel parameter by adding the following line to "/etc/sysctl.conf" (or modify the line to have the required value):
net.ipv4.conf.all.accept_redirects =0
Run the following command to apply this value:
# sysctl --system