Chmod 4750 Explained
Chmod 4750: SUID with owner full access, group read+execute, no access for others. A more secure SUID setup limiting who can execute.
Permission
4750
rwsr-x---
chmod 4750 filename
Permission Breakdown
| Role | Read (4) | Write (2) | Execute (1) | Octal | Meaning |
|---|---|---|---|---|---|
| Owner | r | w | x | 7 | read, write, execute |
| Group | r | - | x | 5 | read, execute |
| Others | - | - | - | 0 | no permissions |
Visual Permission Grid
Detailed Explanation
The permission 4750 sets the SUID bit while restricting execution to the owner and group only, blocking access for others.
Octal breakdown:
- 4 (Special): SUID bit set
- 7 (Owner): read (4) + write (2) + execute (1) = full access
- 5 (Group): read (4) + execute (1) = read and execute
- 0 (Others): no access
In symbolic notation this is rwsr-x---. The s in the owner execute position indicates SUID is active.
This is a more secure alternative to 4755 because it limits who can execute the SUID program. Only the owner and group members can run it, which reduces the attack surface. If an attacker gains access as a user not in the designated group, they cannot exploit the SUID program.
This is the recommended approach for custom SUID applications in enterprise environments: create a specific group for authorized users, set the executable to 4750, and add only the users who need it to the group.
Use Case
Used for custom SUID applications where only specific team members (in the group) should be able to run the program with elevated privileges.