Understanding OWASP Top 10 Vulnerabilities

The OWASP Top 10 represents the most critical security risks to web applications, as identified by the Open Web Application Security Project. This guide explores the 2021 edition of OWASP Top 10, providing practical insights and mitigation strategies.

1. Broken Access Control (Up from #5)

Access control vulnerabilities have moved to #1, with 94% of applications tested for some form of broken access control. These vulnerabilities allow attackers to bypass authorization, viewing or modifying other users' data and accessing unauthorized functionality.

Key vulnerabilities include:

• Insecure Direct Object References (IDOR)
• Path traversal vulnerabilities
• Privilege escalation opportunities
• JWT token manipulation
• CORS misconfiguration

2. Cryptographic Failures (#2)

Previously known as "Sensitive Data Exposure," this category focuses on failures related to cryptography. These failures often lead to sensitive data exposure or system compromise.

Common issues include:

• Transmission of sensitive data in cleartext
• Use of weak cryptographic algorithms or protocols
• Use of default or weak keys
• Lack of proper certificate validation
• Use of deprecated hash functions

3. Injection (#3)

Injection flaws occur when untrusted data is sent to an interpreter as part of a command or query. The most common injection attacks include:

• SQL Injection
• NoSQL Injection
• OS Command Injection
• LDAP Injection
• Expression Language Injection

4. Insecure Design (New)

A new category focusing on design and architectural flaws. Unlike implementation bugs, these issues cannot be fixed by perfect implementation and require secure design patterns.

5. Security Misconfiguration (#6)

Security misconfiguration remains a critical issue, often resulting from:

• Unnecessary features being enabled
• Default accounts/passwords remaining active
• Overly detailed error messages
• Unpatched flaws or outdated software
• Insecure default configurations

6. Vulnerable and Outdated Components (#9)

Components running with full privileges often contain vulnerabilities that can lead to serious security impacts. Key concerns include:

• Unknown versions of components in use
• Vulnerable dependencies
• Unsupported system components
• Irregular vulnerability scanning

7. Identification and Authentication Failures (#2)

Previously "Broken Authentication," this category includes weaknesses in:

• Session management
• Password policies
• Multi-factor authentication implementation
• Session fixation protections

8. Software and Data Integrity Failures (New)

This new category focuses on making assumptions related to software updates, critical data, and CI/CD pipelines without verifying integrity.

9. Security Logging and Monitoring Failures (#10)

Insufficient logging and monitoring lead to:

• Undetected breaches
• Delayed incident response
• Inability to conduct forensic analysis
• Missing audit trails

10. Server-Side Request Forgery (New)

SSRF flaws occur when web applications fetch remote resources without validating user-supplied URLs. The impact can include:

• User-supplied data is not validated, filtered, or sanitized by the application
• Dynamic queries or non-parameterized calls without context-aware escaping are used directly in the interpreter
• Hostile data is used within object-relational mapping (ORM) search parameters to extract additional, sensitive records
• Hostile data is directly used or concatenated, such that the SQL or command contains both structure and hostile data in dynamic queries, commands, or stored procedures

Practical Mitigation Strategies

To protect against these vulnerabilities:

• Implement strong access control mechanisms
• Use up-to-date cryptographic standards
• Validate and sanitize all input
• Adopt secure design patterns
• Regularly update and patch systems
• Implement comprehensive logging and monitoring
• Use security headers and HTTPS
• Conduct regular security assessments

Resources

• OWASP Top 10:2021
• OWASP Cheat Sheet Series
• OWASP Web Security Testing Guide