How to secure /tmp and /dev/shm partitions on servers?

It is highly recommended to mount /tmp and /dev/shm partitions in noexec,nosuid mode in order to prevent files been executed under those partitions. To mount /tmp and /dev/shm in noexec,nosuid more, edit the /etc/fstab file and

nano /etc/fstab

search for the word

"defaults"

in front of the 2 partitions and replace them with

    rw,noexec,nosuid

The entry should look like the following:

    tmpfs /dev/shm tmpfs rw,noexec,nosuid 0 0

and same for /tmp partition as well.
Save the /etc/fstab file. You now need to remount the partitions for the changes to take effect. Execute the following remount commands:

    mount -o remount /tmp
    mount -o remount /dev/shm

You can now check the mounted partitions using the command:

mount | grep tmp