# Password Verification Hook Your company wishes to increase security beyond the requirements of the default password implementation in order to fulfill security or compliance requirements. You plan to track the status of a password sign-in attempt and take action via an email or a restriction on logins where necessary. As this hook runs on unauthenticated requests, malicious users can abuse the hook by calling it multiple times. Pay extra care when using the hook as you can unintentionally block legitimate users from accessing your application. Check if a password is valid prior to taking any additional action to ensure the user is legitimate. Where possible, send an email or notification instead of blocking the user. **Inputs** | Field | Type | Description | | --------- | --------- | ----------------------------------------------------------------------------------------------- | | `user_id` | `string` | Unique identifier for the user attempting to sign in. Correlate this to the `auth.users` table. | | `valid` | `boolean` | Whether the password verification attempt was valid. | ```json { "user_id": "3919cb6e-4215-4478-a960-6d3454326cec", "valid": true } ``` ```json { "type": "object", "properties": { "user_id": { "type": "string", "x-faker": "random.uuid" }, "valid": { "type": "boolean", "x-faker": "random.boolean" } }, "required": ["user_id", "valid"] } ``` **Outputs** Return these only if your hook processed the input without errors. | Field | Type | Description | | -------------------- | --------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `decision` | `string` | The decision on whether to allow authentication to move forward. Use `reject` to deny the verification attempt and log the user out of all active sessions. Use `continue` to use the default Supabase Auth behavior. | | `message` | `string` | The message to show the user if the decision was `reject`. | | `should_logout_user` | `boolean` | Whether to log out the user if a `reject` decision is issued. Has no effect when a `continue` decision is issued. | ```json { "decision": "reject", "message": "You have exceeded maximum number of password sign-in attempts.", "should_logout_user": "false" } ``` As part of new security measures within the company, users can only input an incorrect password every 10 seconds and not more than that. You want to write a hook to enforce this. Create a table to record each user's last incorrect password verification attempt. ```sql create table public.password_failed_verification_attempts ( user_id uuid not null, last_failed_at timestamp not null default now(), primary key (user_id) ); ``` Create a hook to read and write information to this table. For example: ```sql create function public.hook_password_verification_attempt(event jsonb) returns jsonb language plpgsql as $$ declare last_failed_at timestamp; begin if event->'valid' is true then -- password is valid, accept it return jsonb_build_object('decision', 'continue'); end if; select last_failed_at into last_failed_at from public.password_failed_verification_attempts where user_id = event->'user_id'; if last_failed_at is not null and now() - last_failed_at < interval '10 seconds' then -- last attempt was done too quickly return jsonb_build_object( 'error', jsonb_build_object( 'http_code', 429, 'message', 'Please wait a moment before trying again.' ) ); end if; -- record this failed attempt insert into public.password_failed_verification_attempts ( user_id, last_failed_at ) values ( event->'user_id', now() ) on conflict do update set last_failed_at = now(); -- finally let Supabase Auth do the default behavior for a failed attempt return jsonb_build_object('decision', 'continue'); end; $$; -- Assign appropriate permissions grant all on table public.password_failed_verification_attempts to supabase_auth_admin; revoke all on table public.password_failed_verification_attempts from authenticated, anon, public; ``` You can notify a user via email instead of blocking the user. To do so, make use of [Supabase Vault](/docs/guides/database/vault) to store the API Key of our mail provider and use [`pg_net`](/docs/guides/database/extensions/pg_net) to send an HTTP request to our email provider to send the email. Ensure that you have configured a sender signature for the email account which you are sending emails from. First, create a table to track sign in attempts. ```sql create table public.password_sign_in_attempts ( user_id uuid not null, attempt_id uuid not null, last_attempt_at timestamp not null default now(), attempt_successful boolean not null, primary key (user_id, attempt_id) ); ``` Next, store the API key of our email API provider: ```sql select vault.create_secret('my_api_key', 'my_api_key_name', 'description_of_my_api_key'); ``` Create the hook: ```sql create or replace function public.hook_notify_user_on_failed_attempts(event jsonb) returns jsonb language plpgsql as $$ declare user_id uuid; server_token text; user_email_address text; email_body jsonb; response_id int; -- Variable to store the response ID http_code int; error_message jsonb; attempt_count int; max_attempts int := 5; -- Set the threshold for failed attempts begin user_id := (event->>'user_id')::uuid; -- Record the attempt insert into public.password_sign_in_attempts (user_id, attempt_id, last_attempt_at, attempt_successful) values (user_id, (event->>'attempt_id')::uuid, now(), (event->>'valid')::boolean) on conflict (user_id, attempt_id) do update set last_attempt_at = now(), attempt_successful = (event->>'valid')::boolean; -- Check failed attempts and fetch user email select count(*), u.email into attempt_count, user_email_address from public.password_sign_in_attempts a join auth.users u on a.user_id = u.id where a.user_id = user_id and attempt_successful = false and last_attempt_at > (now() - interval '1 day'); -- Notify user if the number of failed attempts exceeds the threshold if attempt_count >= max_attempts then -- Fetch the server token select decrypted_secret into server_token from vault.decrypted_secrets where name = 'my_api_key_name'; -- Prepare the email body email_body := format('{ "from": "yoursenderemail@example.com", "to": "%s", "subject": "Security Alert: Repeated Login Attempts Detected", "textbody": "We have detected repeated login attempts for your account. If this was not you, please secure your account.", "htmlbody": "Security Alert: We have detected repeated login attempts for your account. If this was not you, please secure your account.", "messagestream": "outbound" }', user_email_address)::jsonb; -- Perform the HTTP POST request using Postmark select id into response_id from net.http_post( 'https://api.youremailprovider.com/email', email_body, 'application/json', array['Accept: application/json', 'X-Postmark-Server-Token: ' || server_token] ); -- Fetch the response from net._http_response using the obtained id select status_code, content into http_code, error_message from net._http_response where id = response_id; -- Handle email sending errors if http_code is null or (http_code < 200 or http_code >= 300) then return jsonb_build_object( 'error', jsonb_build_object( 'http_code', coalesce(http_code, 0), 'message', coalesce(error_message ->> 'message', 'error sending email') ) ); end if; end if; -- Continue with default behavior return jsonb_build_object('decision', 'continue'); end; $$; -- Assign appropriate permissions grant execute on function public.hook_notify_user_on_failed_attempts to supabase_auth_admin; revoke execute on function public.hook_notify_user_on_failed_attempts from authenticated, anon, public; grant all on table public.password_sign_in_attempts to supabase_auth_admin; revoke all on table public.password_sign_in_attempts from authenticated, anon, public; ```