Understanding OWASP Top 10: The Bible of Web Vulnerabilities

The OWASP Top 10 is a standard awareness document for developers and web application security. It represents a broad consensus about the most critical security risks to web applications.

The List (2021 Edition)#

1. A01: Broken Access Control

   • Users acting outside of their intended permissions.
   • Fix: Implement role-based access control (RBAC) and deny by default.

2. A02: Cryptographic Failures

   • Previously known as Sensitive Data Exposure.
   • Fix: Encrypt data at rest and in transit (TLS).

3. A03: Injection

   • SQL, NoSQL, OS command injection.
   • Fix: Use parameterized queries (Prepared Statements).

4. A04: Insecure Design

   • Flaws in the design and architecture.
   • Fix: Threat modeling and secure design patterns.

5. A05: Security Misconfiguration

   • Default passwords, verbose error messages, open cloud storage.
   • Fix: Hardening processes and automated configuration audits.

6. A06: Vulnerable and Outdated Components

   • Using libraries with known vulnerabilities.
   • Fix: Software Composition Analysis (SCA) tools.

7. A07: Identification and Authentication Failures

   • Weak passwords, lack of MFA.
   • Fix: Multi-Factor Authentication and strong password policies.

8. A08: Software and Data Integrity Failures

   • Code/updates from untrusted sources.
   • Fix: Code signing and verifying checksums.

9. A09: Security Logging and Monitoring Failures

   • Not detecting attacks in time.
   • Fix: Centralized logging and alerting.

10. A10: Server-Side Request Forgery (SSRF)

    • Fetching a remote resource without validating the user-supplied URL.
    • Fix: Validate and sanitize all user input.

Conclusion#

Memorizing this list isn't enough. You need to understand how these vulnerabilities work to find and fix them.