RHEL 9 must restrict exposed kernel pointer addresses access.
Severity | Group ID | Group Title | Version | Rule ID | Date | STIG Version |
|---|---|---|---|---|---|---|
| medium | V-257800 | SRG-OS-000132-GPOS-00067 | RHEL-09-213025 | SV-257800r1044851_rule | 2025-02-27 | 2 |
| Description |
|---|
| Exposing kernel pointers (through procfs or "seq_printf()") exposes kernel writeable structures, which may contain functions pointers. If a write vulnerability occurs in the kernel, allowing write access to any of this structure, the kernel can be compromised. This option disallows any program without the CAP_SYSLOG capability to get the addresses of kernel pointers by replacing them with "0". Satisfies: SRG-OS-000132-GPOS-00067, SRG-OS-000433-GPOS-00192, SRG-OS-000480-GPOS-00227 |
| ℹ️ Check |
|---|
| Verify the runtime status of the kernel.kptr_restrict kernel parameter with the following command: $ sudo sysctl kernel.kptr_restrict kernel.kptr_restrict = 1 Verify the configuration of the kernel.kptr_restrict kernel parameter with the following command: $ sudo /usr/lib/systemd/systemd-sysctl --cat-config | egrep -v '^(#|;)' | grep -F kernel.kptr_restrict | tail -1 kernel.kptr_restrict =1 If "kernel.kptr_restrict" is not set to "1" or is missing, this is a finding. |
| ✔️ Fix |
|---|
| Add or edit the following line in a system configuration file in the "/etc/sysctl.d/" directory: kernel.kptr_restrict = 1 Reload settings from all system configuration files with the following command: $ sudo sysctl --system |