RHEL 10 must not accept router advertisements on all Internet Protocol version 6 (IPv6) interfaces by default.
Severity | Group ID | Group Title | Version | Rule ID | Date | STIG Version |
|---|---|---|---|---|---|---|
| medium | V-281358 | SRG-OS-000420-GPOS-00186 | RHEL-10-800260 | SV-281358r1167224_rule | 2026-03-11 | 1 |
Description
An illicit router advertisement message could result in a man-in-the-middle attack.
Satisfies: SRG-OS-000420-GPOS-00186, SRG-OS-000142-GPOS-00089
ℹ️ Check
Note: If IPv6 is disabled on the system, this requirement is not applicable.
Verify RHEL 10 does not accept router advertisements on all IPv6 interfaces by default, unless the system is a router.
Check the value of the "net.ipv6.conf.default.accept_ra" variable with the following command:
$ sudo sysctl net.ipv6.conf.default.accept_ra
net.ipv6.conf.default.accept_ra = 0
If "net.ipv6.conf.default.accept_ra" is not set to "0" or is missing, this is a finding.
✔️ Fix
Configure RHEL 10 to not accept router advertisements on all IPv6 interfaces by default, unless the system is a router.
Create a configuration file if it does not already exist:
$ sudo vi /etc/sysctl.d/ipv6_accept_ra.conf
Add the following line to the file:
net.ipv6.conf.default.accept_ra = 0
Reload settings from all system configuration files with the following command:
$ sudo sysctl --system