RHEL-10-800090 - RHEL 10 must ignore Internet Protocol version 4 (IPv4) Internet Control Message Protocol (ICMP) redirect messages.

Information

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

Solution

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

See Also

https://dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_RHEL_10_V1R1_STIG.zip

Item Details

Category: SYSTEM AND COMMUNICATIONS PROTECTION

References: 800-53|SC-5, 800-53|SC-6, CAT|II, CCI|CCI-001096, CCI|CCI-002385, Rule-ID|SV-281341r1167173_rule, STIG-ID|RHEL-10-800090, Vuln-ID|V-281341

Plugin: Unix

Control ID: 2e3491862dedec52850b5b7cbb8ecbfed2c762bf446b02147d9de07fedc0d07a