Mohammad Waseem

Posted on Feb 3

Harnessing SQL for Automated Authentication Flows Without Budget

#security #sql #automation

Automating Authentication Flows Using SQL on a Zero Budget

In today's security landscape, automating authentication and authorization flows is often associated with complex, costly systems involving dedicated identity providers, OAuth servers, or third-party integrations. However, for organizations with limited resources, leveraging existing database systems—primarily SQL—can provide a surprisingly effective, low-cost approach to streamline and secure auth workflows. This post explores how a security researcher, working under zero-budget constraints, can creatively harness SQL for automating auth flows.

Understanding the Core Concept

The foundational idea is to utilize SQL's capabilities—queries, stored procedures, triggers, and views—to manage user authentication status, session tokens, and permission checks directly within the database. By doing so, you can reduce reliance on external components, lower latency, and minimize setup costs.

Setting Up a Minimal User Authentication Schema

Suppose you start with a simple user table:

CREATE TABLE users (
    id INT PRIMARY KEY,
    username VARCHAR(50) UNIQUE,
    password_hash VARCHAR(255), -- Store hashed passwords
    role VARCHAR(20),
    last_login TIMESTAMP
);

This table forms the basis for authenticating users. Passwords should be stored securely using hashes like bcrypt or Argon2, but for simplicity, assume hashes are precomputed.

Creating a Login Function

Next, implement a stored procedure for login validation:

CREATE PROCEDURE login_user(username VARCHAR(50), password_input VARCHAR(255))
AS $$
BEGIN
    SELECT id, password_hash INTO STRICT user_id, stored_hash FROM users WHERE username = username;
    -- Verify password using an external application or extension;
    -- For illustration, assume a function verify_hash exists:
    IF verify_hash(stored_hash, password_input) THEN
        -- Update last login timestamp
        UPDATE users SET last_login = NOW() WHERE id = user_id;
        -- Generate a session token (here, a simple UUID)
        INSERT INTO sessions (user_id, token, issued_at) VALUES (user_id, gen_random_uuid(), NOW());
        RETURN NEXT 'Login successful, token generated!';
    ELSE
        RAISE EXCEPTION 'Invalid credentials';
    END IF;
END;
$$ LANGUAGE plpgsql;

Note: You should replace verify_hash and gen_random_uuid() with actual implementations or extensions, like pgcrypto. For zero-budget, you can implement token generation using existing built-in functions or simple GUID generators.

Managing Sessions and Access Control

Create a sessions table to track active sessions:

CREATE TABLE sessions (
    session_id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    user_id INT REFERENCES users(id),
    token UUID UNIQUE,
    issued_at TIMESTAMP,
    expires_at TIMESTAMP
);

A function to validate tokens:

CREATE FUNCTION validate_session(token UUID) RETURNS BOOLEAN AS $$
DECLARE
    session_record RECORD;
BEGIN
    SELECT * INTO session_record FROM sessions WHERE token = token AND expires_at > NOW();
    RETURN FOUND;
END;
$$ LANGUAGE plpgsql;

This allows application layers or middleware to verify session validity purely through SQL. You can also set triggers or policies that restrict data access based on session validity.

Automating Authorization with SQL

Role-based access can be enforced via views or row-level security policies:

CREATE VIEW user_data AS
SELECT * FROM sensitive_table
WHERE user_id = current_setting('myapp.current_user_id')::INT;

Set the user context programmatically:

SET myapp.current_user_id = '42'; -- dynamically at session start

And leverage PostgreSQL's row-level security to restrict data access automatically:

ALTER TABLE sensitive_table ENABLE ROW LEVEL SECURITY;
CREATE POLICY user_policy ON sensitive_table
    FOR SELECT USING (user_id = current_setting('myapp.current_user_id')::INT);

Limitations and Security Considerations

While SQL-based automations are cost-effective, they demand meticulous security practices:

Ensure passwords are hashed securely.
Protect session tokens via secure, unpredictable generation.
Regularly audit and rotate keys or tokens.
Use role-based permissions within the database.

This strategy is best suited for small-scale applications, prototypes, or environments where external auth providers are impractical. When properly implemented, SQL-based automation facilitates a secure, scalable, zero-cost authentication system.

In conclusion, with creativity and a solid understanding of your database's features, you can craft robust authentication flows without additional expense. This approach underscores the importance of understanding foundational system components and showcases how to maximize their potential in security workflows.

References:

PostgreSQL Documentation on Security and Authentication
OWASP Best Practices for Password Storage
Open Source crypto extensions like pgcrypto

🛠️ QA Tip

Pro Tip: Use TempoMail USA for generating disposable test accounts.

DEV Community