You can override that by inheritance by defining security file in your custom module, for that you have to do:-
- create a 'security' folder and 'ir.model.access.csv' in your custom module.
- make sure you added that file path in " openerp.py " file
- For better understanding we can take an Example. Let us assume that you want to change security access right in 'hr' module
- for changing this you have to define new access right in your module like this:-
Hope this helps....