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-217292 | SLES-12-030400 | SV-217292r991589_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-217292r991589_chk)
Verify the SUSE operating system ignores IPv4 ICMP redirect messages.
Check the value of the "accept_redirects" variables with the following command:
# sysctl net.ipv4.conf.default.accept_redirects
net.ipv4.conf.default.accept_redirects = 0
If the returned line does not have a value of "0" this is a finding.
Fix Text (F-18518r370033_fix)
Configure the SUSE operating system ignores IPv4 ICMP redirect messages by adding the following line to "/etc/sysctl.conf" (or modify the line to have the required value):
net.ipv4.conf.default.accept_redirects = 0
Run the following command to apply this value:
# sysctl --system