Hi Manjush,
I don't think there is a way to restrict access to Security folder.
And the same goes for Catalog folder, people can see all the schemas available but they can't see the data or make changes to any schema unless they are authorized to do so.
If you want to restrict this access for end users then create end users as restricted users and then they won't be able to access HANA Studio using their credentials.
Regards,
Vivek