OWASP Top 10 2025: What Security Teams Need to Know

Introduction

The OWASP Top 10 remains the most authoritative reference for web application security risks. The 2025 edition reflects the rapidly evolving threat landscape, incorporating lessons from thousands of real-world breaches and vulnerability assessments. For security teams, understanding these changes isn't optional — it's foundational to protecting modern applications.

This guide breaks down each category, highlights what changed from the 2021 edition, provides practical examples, and shows how organizations can proactively address these risks.

What Changed from 2021 to 2025

The 2025 update reflects several macro trends: the explosion of AI-powered applications, increased API attack surfaces, software supply chain compromises, and the continued shift toward cloud-native architectures. Notable changes include the elevation of Server-Side Request Forgery (SSRF) concerns, expanded focus on supply chain integrity, and new emphasis on AI/ML-specific vulnerabilities.

A01: Broken Access Control

Broken Access Control remains the #1 risk. Attackers exploit weak enforcement of what authenticated users are allowed to do — accessing other users' data, modifying permissions, or escalating privileges.

Practical Example: A user modifies a URL parameter from /api/orders/123 to /api/orders/456 and accesses another customer's order details because the backend doesn't verify ownership.

Mitigation: Implement server-side access control checks on every request. Use deny-by-default policies. Enforce record-level ownership validation.

A02: Cryptographic Failures

Previously "Sensitive Data Exposure," this category focuses on failures related to cryptography — weak algorithms, improper key management, unencrypted data in transit or at rest.

Practical Example: An application stores passwords using MD5 hashing without salts, making rainbow table attacks trivial. Or TLS 1.0 is still enabled on production servers.

Mitigation: Use strong algorithms (AES-256, bcrypt/argon2 for passwords). Enforce TLS 1.3. Rotate keys regularly. Audit certificate management.

A03: Injection

Injection attacks remain critical. SQL injection, NoSQL injection, OS command injection, and LDAP injection all exploit untrusted data sent to interpreters.

Practical Example: A search form passes user input directly into a SQL query: SELECT * FROM users WHERE name = '${input}' — allowing attackers to extract the entire database.

Mitigation: Use parameterized queries and prepared statements exclusively. Validate and sanitize all input. Apply the principle of least privilege to database accounts.

A04: Insecure Design