Address space layout randomization (ASLR) must be implemented by SLEM 5 to protect memory from unauthorized code execution.

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.

Verify SLEM 5 implements Address space layout randomization (ASLR) with the following command:

     > sudo sysctl kernel.randomize_va_space
     kernel.randomize_va_space = 2

If the kernel parameter "randomize_va_space" is not equal to "2", or nothing is returned, this is a finding.

Configure SLEM 5 to implement ASLR by running the following command as an administrator:

     > sudo sysctl -w kernel.randomize_va_space=2

If "2" is not the system's default value, add or update the following line in "/etc/sysctl.d/99-stig.conf":

     > sudo sh -c 'echo "kernel.randomize_va_space=2" >> /etc/sysctl.d/99-stig.conf'

Reload settings from all system configuration files with the following command:

     > sudo sysctl --system