SQL Injection: How to Audit and Fix Vulnerabilities

How SQL Injection Works

Imagine a login form. Typically, the code might look like this: SELECT * FROM users WHERE username = '$username' AND password = '$password'

If an attacker enters ' OR '1'='1 in the username field, the query becomes: SELECT * FROM users WHERE username = '' OR '1'='1' AND password = '' The database will return the first user (usually the Admin) because 1=1 is always true.

3 Pillars of SQLi Prevention

1. Prepared Statements (Parameterized Queries)

This is the gold standard. Instead of sending the full query as a string, you send the "template" first and then send the data separately. The database treats the data as literal text, never as part of the command.

2. Input Validation & Sanitization

Only allow the characters you expect. If you're asking for a phone number, don't allow letters or symbols like ' or --.

3. Principle of Least Privilege

Your web application should not connect to the database using the "Root" user. Create a specific user that only has access to the database tables it actually needs.

Auditing Your Own Site

Use tools like SQLMap or OWASP ZAP to scan your applications for potential entry points. At AmanaFlow, our WAF (Web Application Firewall) automatically detects and blocks 99% of SQLi attempts at the network edge.

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FAQ

Q: Does WordPress protect against SQLi?
A: Yes, the WordPress core uses the $wpdb->prepare() function. However, poorly coded plugins often introduce vulnerabilities.

Q: Can SQLi delete my entire database?
A: Yes. If the user has "DELETE" or "DROP" privileges, an attacker can wipe your entire data infrastructure with a single line of code.