OWASP Top 10 2021: A Guide to Web Application Security

1. Broken Access Control (A01:2021)

Broken access control refers to the failure to properly restrict user actions based on their role. Attackers can exploit this vulnerability to access unauthorized data or functions. Proper access controls are crucial to ensuring that users can only perform actions permitted by their roles, and misconfigurations can lead to significant security risks.

2. Cryptographic Failures (A02:2021)

Previously known as "Sensitive Data Exposure," this category focuses on improper implementation of cryptography that compromises data security. This includes the lack of encryption, weak encryption methods, or incorrect key management. Securing sensitive data, both in transit and at rest, is essential for maintaining privacy and trust.

3. Injection (A03:2021)

Injection flaws occur when untrusted data is sent to an interpreter, which then executes unintended commands or queries. SQL injection, command injection, and others are common forms of this vulnerability. Developers must sanitize inputs and employ secure coding practices to protect against injection attacks.

4. Insecure Design (A04:2021)

This new category focuses on flaws in the design phase of development. Insecure design flaws can stem from a lack of security consideration early in the development lifecycle. Addressing security in the design process helps to build applications with stronger security foundations.

5. Security Misconfiguration (A05:2021)

Security misconfigurations occur when an application, server, or database is improperly set up, leaving it vulnerable. This can include default settings, unnecessary services running, or overly permissive permissions. Regular security audits and applying secure default configurations can help mitigate these risks.

6. Vulnerable and Outdated Components (A06:2021)

Using outdated or vulnerable libraries and components is a common source of security flaws. Developers should stay up-to-date on patches and updates for third-party components to prevent attackers from exploiting known vulnerabilities.

7. Identification and Authentication Failures (A07:2021)

This category highlights flaws in the authentication process, including weak passwords, missing multi-factor authentication, and incorrect session management. Securing user identities with strong authentication methods is critical to protect against unauthorized access.

8. Software and Data Integrity Failures (A08:2021)

This focuses on vulnerabilities related to software supply chain attacks and improper validation of data. Ensuring that code, updates, and data are verified and trusted is essential for preventing integrity failures that can be exploited by attackers.

9. Security Logging and Monitoring Failures (A09:2021)

Lack of proper logging and monitoring makes it difficult to detect and respond to attacks. Implementing comprehensive logging and continuous monitoring allows organizations to identify and mitigate security incidents more effectively.

10. Server-Side Request Forgery (SSRF) (A10:2021)

SSRF vulnerabilities occur when an attacker tricks the server into making unauthorized requests to internal resources. Proper input validation and limiting network access for servers can help mitigate SSRF attacks.

The OWASP Top 10 2021 serves as a guide for developers to recognize and address the most critical web application security risks. By following best practices and continuously evolving security measures, organizations can significantly reduce their exposure to cyber threats.