You could have a script that checks the user's security level and attach it to a transparent button over that tab. Have script send them to an allowed tab if they do not have permissions to view that tab.
Isn't this a Layout rather than a Tab? I don't see any tab control in your screen shot.
If the entire layout shown is to be restricted, you can set restrictions in manage security to control access to the layout and buttons that take the user to such a layout can perform a script that includes code that checks the user's privilege set name to determine whether or not they have access to the layout. (This avoids presenting them with a greyed out "access denied" screen.)