OWASP Top 10:2025 Quick Reference

OWASP Top 10:2025 Quick Reference

Overview

The OWASP Top 10 is a standard awareness document representing the most critical security risks to web applications. This is the 2025 version with updated categories based on current threat landscape.

A01:2025 - Broken Access Control

Risk: Users acting outside their intended permissions.

Common Vulnerabilities:

• Missing authentication on endpoints
• Missing authorization checks (IDOR)
• Privilege escalation
• CORS misconfiguration
• Forced browsing to authenticated pages

Detection Patterns:

// Missing auth check
export async function DELETE(request) { ... }

// Missing ownership verification
const doc = await db.doc.findUnique({ where: { id } });  // No user filter

Prevention:

• Deny by default
• Implement access control mechanisms once, reuse throughout
• Log access control failures

A02:2025 - Cryptographic Failures

Risk: Exposure of sensitive data due to weak cryptography.

Common Vulnerabilities:

• Transmitting data in clear text (HTTP)
• Using weak/deprecated algorithms (MD5, SHA1, DES)
• Hardcoded encryption keys
• Missing encryption for sensitive data

Detection Patterns:

// Weak hashing
const hash = crypto.createHash('md5').update(password).digest('hex');

// Hardcoded keys
const SECRET_KEY = 'my-secret-key-123';

Prevention:

• Use TLS for all data transmission
• Use strong algorithms (AES-256, SHA-256+, bcrypt)
• Store secrets in environment variables

A03:2025 - Software Supply Chain Failures (NEW)

Risk: Vulnerabilities introduced through dependencies.

Common Vulnerabilities:

• Using packages with known CVEs
• No dependency verification
• Typosquatting attacks
• Compromised build pipelines

Detection:

npm audit
yarn audit
npx snyk test

Prevention:

• Regular dependency audits
• Lock file verification
• Use Dependabot or similar
• Verify package integrity

A04:2025 - Security Misconfiguration

Risk: Insecure default configurations or incomplete setup.

Common Vulnerabilities:

• Unnecessary features enabled
• Default accounts/passwords
• Verbose error messages
• Missing security headers
• Outdated software

Detection Patterns:

// Verbose errors in production
if (error) {
  res.status(500).json({ error: error.stack });  // Exposes internals
}

// Missing security headers
// No Content-Security-Policy, X-Frame-Options, etc.

Prevention:

• Minimal platform, remove unused features
• Review and update configurations regularly
• Implement security headers

A05:2025 - Injection

Risk: Untrusted data sent to an interpreter.

Types:

• SQL Injection
• NoSQL Injection
• Command Injection
• LDAP Injection
• XSS (Cross-Site Scripting)

Detection Patterns:

// SQL Injection
query(`SELECT * FROM users WHERE id = ${userId}`);

// Command Injection
exec(`ls ${userInput}`);

// XSS
element.innerHTML = userInput;

Prevention:

• Use parameterized queries
• Validate and sanitize input
• Use ORM/ODM properly
• Escape output

A06:2025 - Insecure Design

Risk: Security flaws in the application architecture.

Common Issues:

• No threat modeling
• Missing security requirements
• Lack of secure design patterns
• No rate limiting

Examples:

• Password reset via security questions only
• No brute force protection
• Trust boundaries not defined

Prevention:

• Threat modeling during design
• Secure design patterns
• Reference architectures
• Unit and integration testing for security

A07:2025 - Authentication Failures

Risk: Identity, authentication, or session management flaws.

Common Vulnerabilities:

• Weak passwords allowed
• Credential stuffing susceptibility
• Missing MFA
• Session fixation
• Improper session invalidation

Detection Patterns:

// Weak password validation
if (password.length >= 4) { ... }

// Session not invalidated on logout
function logout() {
  redirect('/login');  // Session still valid!
}

Prevention:

• Implement MFA
• Strong password requirements
• Secure session management
• Account lockout policies

A08:2025 - Software and Data Integrity Failures

Risk: Code/data modifications without verification.

Common Vulnerabilities:

• Insecure deserialization
• CI/CD pipeline vulnerabilities
• Auto-update without verification
• Unsigned code/packages

Detection Patterns:

// Unsafe deserialization
const data = JSON.parse(userInput);  // Then using as trusted
const obj = eval('(' + userInput + ')');

Prevention:

• Digital signatures for code/updates
• Integrity verification for CI/CD
• Review code changes
• Serialization validation

A09:2025 - Security Logging and Alerting Failures

Risk: Inability to detect, escalate, or respond to attacks.

Common Issues:

• No logging of authentication events
• No alerting on suspicious activity
• Logs stored only locally
• Sensitive data in logs

Detection:

// No logging
export async function login(credentials) {
  // No audit trail of login attempts
}

// Sensitive data in logs
console.log(`User ${email} logged in with password ${password}`);

Prevention:

• Log authentication events
• Log access control failures
• Centralized log management
• Alerting thresholds

A10:2025 - Mishandling of Exceptional Conditions (NEW)

Risk: Improper error handling leading to security issues.

Common Vulnerabilities:

• Failing open instead of closed
• Information disclosure in errors
• Uncaught exceptions
• Race conditions

Detection Patterns:

// Failing open
try {
  verifyToken(token);
} catch {
  // Silently continues - user is now "authenticated"!
}

// Information disclosure
catch (error) {
  return res.json({ error: error.message, stack: error.stack });
}

Prevention:

• Fail securely (deny by default)
• Generic error messages to users
• Detailed logging internally
• Handle all exceptions

Quick Reference Table

Resources

• OWASP Top 10:2025
• OWASP Cheat Sheet Series
• OWASP Testing Guide
• OWASP ASVS