SQL Security & Injection Prevention
Secure databases — prevent SQL injection, encrypt sensitive data, audit access, and implement defense-in-depth for database security.
55 min•By Priygop Team•Last updated: Feb 2026
SQL Security Best Practices
- SQL Injection: Attacker input: ' OR '1'='1 turns SELECT * FROM users WHERE name = '' OR '1'='1' — returns all rows. Caused by string concatenation in queries. #1 web application vulnerability
- Prevention: Prepared statements (parameterized queries) — database separates SQL structure from data. $stmt = $pdo->prepare('SELECT * FROM users WHERE id = ?'); $stmt->execute([$id])
- Encryption at Rest: TDE (Transparent Data Encryption) — encrypts database files on disk. Protects against stolen disks/backups. MySQL: InnoDB tablespace encryption. PostgreSQL: pgcrypto
- Encryption in Transit: SSL/TLS connections — REQUIRE SSL in MySQL user grants. Encrypts data between application and database. Prevents network sniffing of queries and credentials
- Audit Logging: Track who accessed what data and when — pgAudit (PostgreSQL), MySQL Enterprise Audit. Required for compliance (GDPR, HIPAA, SOC2). Log SELECT on sensitive tables
- Row-Level Security (RLS): PostgreSQL policies — CREATE POLICY user_isolation ON orders USING (user_id = current_user_id()). Each user sees only their own rows. Multi-tenant data isolation