Hi,

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

access_hr_employee_user,hr.employee user,model_hr_employee,base.group_hr_user,1,1,1,1

- for changing this you have to define new access right in your module like this:-

hr.access_hr_employee_user,hr.employee user,model_hr_employee,base.group_hr_user,1,0,0,0 

Hope this helps....