RHEL 10 must ignore Internet Protocol version 4 (IPv4) Internet Control Message Protocol (ICMP) redirect messages.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
| V-281341 | RHEL-10-800090 | SV-281341r1167173_rule | CCI-002385 | 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. This feature of the IPv4 protocol has few legitimate uses. It should be disabled unless absolutely required. Satisfies: SRG-OS-000420-GPOS-00186, SRG-OS-000142-GPOS-00072 | ||||
| STIG | Date | |||
| Red Hat Enterprise Linux 10 Security Technical Implementation Guide | 2026-03-11 | |||
Details
Check Text (C-281341r1167173_chk)
Verify RHEL 10 will not accept IPv4 ICMP redirect messages.
Check the value of all "net.ipv4.conf.all.accept_redirects" variables with the following command:
$ sudo sysctl net.ipv4.conf.all.accept_redirects
net.ipv4.conf.all.accept_redirects = 0
If "net.ipv4.conf.all.accept_redirects" is not set to "0" or is missing, this is a finding.
Fix Text (F-85807r1167172_fix)
Configure RHEL 10 to ignore IPv4 ICMP redirect messages.
Create a configuration file if it does not already exist:
$ sudo vi /etc/sysctl.d/99-ipv4_accept_redirects.conf
Add the following line to the file:
net.ipv4.conf.all.accept_redirects = 0
Reload settings from all system configuration files with the following command:
$ sudo sysctl --system