The Linux operating system assigns a unique identifier to every user. This identifier is called the user ID or UID. The Linux system also assigns a group ID (GID) to each account that is associated with it. SUID stands for Set User ID and it is an attribute of files in Unix-like OS that determines what operations the file's owner can perform on the file versus what operations other users can perform on the file. A SUID program runs with the permissions of its owner rather than with those of its original (non-owner) user and group.