Introduction

Linux has several access attributes that can allow users or groups to perform certain actions against files, such as execute, modify or view files.

SUID (Set User Identification) and GUID (Set Group Identification) are permissions that allow users to execute a binary or script with the permissions of its owner (SUID) or of its group (GUID).

Some binaries have this permission by default as they require to perform certain actions with elevated privileges, for example the passwd binary needs to run as root in order to change a user’s password, although certain binaries can be exploited to escalate privileges if they have the SUID bit set.