Nutanix OS must mount /dev/shm with secure options.

Control of program execution is a mechanism used to prevent execution of unauthorized programs. Some operating systems may provide a capability that runs counter to the mission or provides users with functionality that exceeds mission requirements. This includes functions and services installed at the operating system level.

Some of the programs, installed by default, may be harmful or may not be necessary to support essential organizational operations (e.g., key missions, functions). Removal of executable programs is not always possible; therefore, establishing a method of preventing program execution is critical to maintaining a secure system baseline.

Methods for complying with this requirement include restricting program execution in certain environments, while preventing execution in other environments; or limiting execution of certain program functionality based on organization-defined criteria (e.g., privileges, subnets, sandboxed environments, or roles).

Verify in Nutanix OS that the "nodev","nosuid", and "noexec" options are configured for /dev/shm using the following command.

$ cat /etc/fstab | grep /dev/shm tmpfs /dev/shm tmpfs defaults,size=512m,noexec,rw,seclabel,nosuid,nodev 0 0

If /dev/shm is mounted without secure options "nodev", "nosuid", and "noexec", this is a finding.

Nutanix OS is designed and engineered to have mount option preconfigured by default and changes are not supported. If any mount options are found, then some corruption has occurred and the OS must be rebuilt.