What is OWASP Top 10?
OWASP Top 10 is a standardized list of the ten most critical security risks for web applications, created and regularly updated by the OWASP (Open Web Application Security Project) community. The list is based on real-world data from security incidents and expert analyses from around the globe.
Why is OWASP Top 10 Important?
The OWASP Foundation is an international nonprofit organization dedicated to improving software security. The community comprises thousands of security experts, developers, and organizations who collectively share knowledge and create open-source tools for application security.
- Industry standard - Used by organizations worldwide as a reference point for application security
- Data-driven - 8 out of 10 categories are derived from analysis of real-world security incidents
- Regular updates - The list is updated every 3-4 years to reflect emerging threats
- Compliance requirements - Many regulations (PCI DSS, GDPR, NIS2) reference the OWASP Top 10
- DevSecOps foundation - A key reference material for implementing DevSecOps processes
Statistic: According to OWASP data, over 94% of applications have some form of vulnerability from the Top 10 categories. The average application contains vulnerabilities spanning 5-6 different categories.
OWASP Top 10 (2021) - Complete List
The list is ranked by importance and frequency of occurrence. First position = most common and most dangerous threat.
Broken Access Control Critical
Broken access control
What it is: The application fails to properly enforce who has access to which resources and functions.
94% of applications have some form of this vulnerability
Attack examples:
- Direct URL manipulation to access other users' data
- Phishing and session hijacking
- Accessing admin functions without authorization
- IDOR (Insecure Direct Object Reference)
How to defend:
- Implement robust authentication and authorization
- Deny by default
- Server-side validation
- Multi-factor authentication (MFA)
Cryptographic Failures Critical
Cryptographic failures
What it is: Weak or missing encryption of data, leading to exposure of sensitive information.
Attack examples:
- Using HTTP instead of HTTPS
- Weak encryption algorithms (MD5, SHA1)
- Hardcoded credentials in code
- Unencrypted databases with passwords
How to defend:
- Always use HTTPS/TLS
- Strong encryption (AES-256)
- bcrypt/Argon2 for passwords
- Secret management (Vault)
Injection Critical
Injection attacks
What it is: An attacker injects malicious code into the application, which is then executed as part of a legitimate command.
Types of injection:
- SQL Injection - manipulation of database queries
- XSS - injection of JavaScript
- Command Injection - system commands
- Template Injection
SQL Injection Example:
How to defend:
- Parameterized queries
- Input validation
- ORM frameworks
Insecure Design High
Insecure design
What it is: Security flaws originating in the application design phase.
Key aspects:
- Threat modeling - threat analysis before development
- Secure design patterns
- Security requirements from the start
- Business logic validation
How to defend:
- Threat modeling sessions
- Secure by design principles
- Security champions in teams
- Design reviews
Security Misconfiguration High
Security misconfiguration
What it is: Incorrect security configuration settings at any level of the application stack.
Common mistakes:
- Default credentials (admin/admin)
- Unnecessarily open ports
- Verbose error messages
- Unpatched software
- Public S3 buckets
How to defend:
- Automated security scans
- Infrastructure as Code
- Regular security audits
Vulnerable Components High
Vulnerable dependencies
What it is: Using libraries and components with known security vulnerabilities.
Modern applications contain 80-90% of code from open-source libraries.
Examples:
- Outdated npm packages
- Log4Shell (CVE-2021-44228)
- Heartbleed in OpenSSL
How to defend:
- SCA tools - Snyk, Dependabot
- Regular updates
- SBOM
Authentication Failures High
Authentication failures
What it is: Weak implementation of authentication and session management.
Common issues:
- Weak passwords without policy enforcement
- Credential stuffing attacks
- Missing MFA
- Poor session token management
How to defend:
- Implement MFA
- Strong password policy
- Rate limiting
- OAuth2 / OpenID Connect
Integrity Failures High
Software and data integrity failures
What it is: Code and infrastructure without protection against integrity violations.
Examples:
- Supply chain attacks (SolarWinds)
- Unverified updates
- Insecure deserialization
- Compromised CI/CD pipelines
How to defend:
- Code signing
- SBOM
- CI/CD pipeline security
- Integrity checks
Logging/Monitoring Failures High
Insufficient logging and monitoring
What it is: Absent or insufficient logging of security events.
Impact:
- Attacks remain undetected
- Inability to perform forensic analysis
- Compliance violations
What to log:
- Failed login attempts
- Access control failures
- Input validation errors
- Administrative actions
How to defend:
- SIEM systems - Splunk, ELK
- Centralized logging
- Real-time alerting
Server-Side Request Forgery High
SSRF
What it is: An attacker forces the server to make an HTTP request to a target of the attacker's choosing.
SSRF Attack Example:
Impact:
- Access to internal systems
- Cloud metadata leaks
- Port scanning
How to defend:
- Whitelist allowed URLs
- Network segmentation
- Input validation
How to Implement Protection
DevSecOps Approach
Protection against the OWASP Top 10 requires integrating security into the entire development lifecycle:
1. Design Phase
- Threat modeling sessions
- Security requirements
- Architecture security review
2. Development Phase
- SAST - SonarQube, Checkmarx
- SCA - Snyk, Dependabot
- Secure coding guidelines
3. Testing Phase
- DAST - OWASP ZAP, Burp Suite
- Penetration testing
- Security test cases
4. Deployment Phase
- Configuration validation
- Infrastructure scanning
- Security gates in CI/CD
5. Operations Phase
- Runtime monitoring
- WAF
- Incident response
6. Continuous Phase
- Vulnerability management
- Patch management
- Security training
Recommended Tools
- SAST: SonarQube, Checkmarx, Semgrep, CodeQL
- DAST: OWASP ZAP, Burp Suite, Acunetix
- SCA: Snyk, WhiteSource, Dependabot
- IaC Scanning: Checkov, tfsec, Terrascan
- Container Scanning: Trivy, Aqua, Clair
- Secrets Detection: GitGuardian, TruffleHog
- WAF: AWS WAF, Cloudflare, ModSecurity