Title

The Ubuntu operating system must implement non-executable data to protect its memory from unauthorized code execution. (Cat II impact)

Discussion

Some adversaries launch attacks with the intent of executing code in non-executable 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.

Check Content

Verify the NX (no-execution) bit flag is set on the system. Check that the no-execution bit flag is set with the following commands: # dmesg | grep NX [ 0.000000] NX (Execute Disable) protection: active If "dmesg" does not show "NX (Execute Disable) protection" active, check the cpuinfo settings with the following command: # less /proc/cpuinfo | grep -i flags flags : fpu vme de pse tsc ms nx rdtscp lm constant_tsc If "flags" does not contain the "nx" flag, this is a finding.

Fix Text

The NX bit execute protection must be enabled in the system BIOS.

Additional Identifiers

Rule ID: SV-215119r610931_rule

Vulnerability ID: V-215119

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

Expert Comments

CCIs tied to check.

Controls tied to check. These are derived from the CCIs shown above.