Web Application Security: OWASP Top 10 Vulnerability Deep Dive and Developer Protection Practices
Application security is one of software engineering’s most overlooked and expensive forms of technical debt. The cost of a production system breach — legal liability, user trust loss, remediation — typically far exceeds the cost of security practices during development. OWASP (Open Web Application Security Project) is the most important nonprofit in web security, and its Top 10 list is the application security industry benchmark.
A01: Broken Access Control
Ranked #1 in the 2021 OWASP Top 10 (surpassing SQL injection). Core problem: the application doesn’t properly verify whether a user has permission to perform the requested operation. Classic cases: modifying URL parameters (`/api/orders/123` → `/api/orders/124`) to access another user’s order (IDOR, insecure direct object reference); regular users accessing admin functionality via crafted requests; JWT token signature validation skipped.
Defense: perform business-layer authorization checks at every API endpoint (“does the current user have access to this resource?”), never rely on client-supplied user IDs — always derive current user identity from server-side auth context.
A03: Injection
SQL injection is one of the oldest web vulnerabilities. Modern ORMs (Sequelize, SQLAlchemy, Hibernate) parameterize queries automatically when used correctly — the most effective defense. But vulnerabilities still appear when developers manually concatenate SQL strings. Parameterized queries are the non-negotiable solution.
A07: Identification and Authentication Failures
Common issues: weak password policies, insecure password storage (MD5/SHA1 instead of bcrypt/argon2), session tokens transmitted in URLs, missing login rate limiting (enabling brute force), non-expiring or predictable password reset tokens.
Recommended tools: OWASP Dependency-Check scans known-vulnerable dependencies; Snyk continuously monitors dependency security; Burp Suite for security testing.
