Title

NixOS must implement nonexecutable data to protect its memory from unauthorized code execution. (Cat II impact)

Discussion

Some adversaries launch attacks with the intent of executing code in nonexecutable regions of memory or in memory locations that are prohibited. Security safeguards employed to protect memory include, for example, data execution prevention and address space layout randomization. Data execution prevention safeguards can either be hardware-enforced or software-enforced with hardware providing the greater strength of mechanism. Examples of attacks are buffer overflow attacks. Satisfies: SRG-OS-000433-GPOS-00192, SRG-OS-000132-GPOS-00067

Check Content

Verify NixOS prevents internal kernel addresses from being leaked with the following command: $ sudo sysctl kernel.kptr_restrict kernel.kptr_restrict = 1 If "kernel.kptr_restrict" does not have a value of "1" or is missing, this is a finding.

Fix Text

Configure NixOS to prevent internal kernel addresses from being leaked by editing /etc/nixos/configuration.nix to add the following: boot.kernel.sysctl = { "kernel.kptr_restrict" = 1; }; Rebuild the system with the following command: $ sudo nixos-rebuild switch

Additional Identifiers

Rule ID: SV-268160r1039368_rule

Vulnerability ID: V-268160

Group Title: SRG-OS-000433-GPOS-00192

Expert Comments

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