findyourpilot/.agent/skills/supabase-postgres-best-practices/references/security-privileges.md

title, impact, impactDescription, tags

title	impact	impactDescription	tags
Apply Principle of Least Privilege	MEDIUM	Reduced attack surface, better audit trail	privileges, security, roles, permissions

Apply Principle of Least Privilege

Grant only the minimum permissions required. Never use superuser for application queries.

Incorrect (overly broad permissions):

-- Application uses superuser connection
-- Or grants ALL to application role
grant all privileges on all tables in schema public to app_user;
grant all privileges on all sequences in schema public to app_user;

-- Any SQL injection becomes catastrophic
-- drop table users; cascades to everything

Correct (minimal, specific grants):

-- Create role with no default privileges
create role app_readonly nologin;

-- Grant only SELECT on specific tables
grant usage on schema public to app_readonly;
grant select on public.products, public.categories to app_readonly;

-- Create role for writes with limited scope
create role app_writer nologin;
grant usage on schema public to app_writer;
grant select, insert, update on public.orders to app_writer;
grant usage on sequence orders_id_seq to app_writer;
-- No DELETE permission

-- Login role inherits from these
create role app_user login password 'xxx';
grant app_writer to app_user;

Revoke public defaults:

-- Revoke default public access
revoke all on schema public from public;
revoke all on all tables in schema public from public;

Reference: Roles and Privileges