effective IDs by calling setfsuid (2) and setfsgid (2). • Supplementary group IDs. This ... effective user (group) ID. setfsuid (2) ( setfsgid (2)) Modify the process's filesystem …relevant system calls include setgid (2), setfsgid (2), setregid (2), setresgid (2), and setgroupsinstead of the effective group ID. See setfsgid (2). Bypassing permission checks: superuser and capabilities