AlmaLinux OS 9 must clear the page allocator to prevent use-after-free attacks.
An XCCDF Rule
Description
Poisoning writes an arbitrary value to freed pages, so any modification or reference to that page after being freed or before being initialized will be detected and prevented. This prevents many types of use-after-free vulnerabilities at little performance cost. This also prevents data leaks and detects corrupted memory.
- ID
- SV-269293r1050175_rule
- Version
- ALMA-09-024110
- Severity
- Medium
- References
- Updated
Remediation Templates
A Manual Procedure
Configure AlmaLinux OS 9 to enable page poisoning with the following commands:
$ grubby --update-kernel=ALL --args="page_poison=1"
Add or modify the following line in "/etc/default/grub" to ensure the configuration survives kernel updates:
GRUB_CMDLINE_LINUX="page_poison=1"