RHEL-09-212040 - RHEL 9 must clear the page allocator to prevent use-after-free attacks.

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Information

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. Also prevents leak of data and detection of corrupted memory.

Satisfies: SRG-OS-000480-GPOS-00227, SRG-OS-000134-GPOS-00068

Solution

Configure RHEL 9 to enable page poisoning with the following commands:

$ sudo 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'

See Also

https://dl.dod.cyber.mil/wp-content/uploads/stigs/U_RHEL_9_V1R1_STIG.zip

Item Details

References: CAT|II, CCI|CCI-000366, CCI|CCI-001084, Rule-ID|SV-257793r925366_rule, STIG-ID|RHEL-09-212040, Vuln-ID|V-257793

Plugin: Unix

Control ID: 6ef3dce809f9fb39610d76253b002e7ddb678b4431f0478e2f89c7dc3891c541