RHEL 9 must enable mitigations against processor-based vulnerabilities.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-257795	RHEL-09-212050	SV-257795r925372_rule		Low

Description
Kernel page-table isolation is a kernel feature that mitigates the Meltdown security vulnerability and hardens the kernel against attempts to bypass kernel address space layout randomization (KASLR). Satisfies: SRG-OS-000433-GPOS-00193, SRG-OS-000095-GPOS-00049

STIG	Date
Red Hat Enterprise Linux 9 Security Technical Implementation Guide	2023-12-01

Details

Check Text ( C-61536r925370_chk )
Verify RHEL 9 enables kernel page-table isolation with the following command: $ sudo grubby --info=ALL \| grep pti args="ro crashkernel=auto resume=/dev/mapper/rhel-swap rd.lvm.lv=rhel/root rd.lvm.lv=rhel/swap rhgb quiet fips=1 audit=1 audit_backlog_limit=8192 pti=on If the "pti" entry does not equal "on", or is missing, this is a finding. Check that kernel page-table isolation is enabled by default to persist in kernel updates: $ sudo grep pti /etc/default/grub GRUB_CMDLINE_LINUX="pti=on" If "pti" is not set to "on", is missing or commented out, this is a finding.

Check Text ( C-61536r925370_chk )

Verify RHEL 9 enables kernel page-table isolation with the following command:

$ sudo grubby --info=ALL | grep pti

args="ro crashkernel=auto resume=/dev/mapper/rhel-swap rd.lvm.lv=rhel/root rd.lvm.lv=rhel/swap rhgb quiet fips=1 audit=1 audit_backlog_limit=8192 pti=on

If the "pti" entry does not equal "on", or is missing, this is a finding.

Check that kernel page-table isolation is enabled by default to persist in kernel updates:

$ sudo grep pti /etc/default/grub

GRUB_CMDLINE_LINUX="pti=on"

If "pti" is not set to "on", is missing or commented out, this is a finding.

Fix Text (F-61460r925371_fix)
Configure RHEL 9 to enable kernel page-table isolation with the following command: $ sudo grubby --update-kernel=ALL --args="pti=on" Add or modify the following line in "/etc/default/grub" to ensure the configuration survives kernel updates: GRUB_CMDLINE_LINUX="pti=on"