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RHEL-10-701060 RHEL 10 must restrict exposed kernel pointer address access.

DISA STIG library V1R3
All changes in this version
first version loaded CAT II

Maps to SC-2, SI-16 via CCI-001082, CCI-002824

Title

RHEL 10 must restrict exposed kernel pointer address access.

Control

Verify RHEL 10 is configured to restrict exposed kernel pointer address access. Verify the runtime status of the "kernel.kptr_restrict" kernel parameter with the following command: $ sudo sysctl kernel.kptr_restrict kernel.kptr_restrict = 1 If "kernel.kptr_restrict" is not set to "1" or is missing, this is a finding.

Discussion

Exposing kernel pointers (through procfs or "seq_printf()") exposes kernel writable 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

Related controls

CCI-001082, CCI-002824

Fix

Configure RHEL 10 to restrict exposed kernel pointer address access. Create a drop-in if it does not already exist: $ sudo vi /etc/sysctl.d/99-kernel_kptr_restrict.conf Add the following to the file: kernel.kptr_restrict = 1 Reload settings from all system configuration files with the following command: $ sudo sysctl --system