OWASP Top 10 Web Vulnerabilities Explained: A Guide for Developers

The OWASP Top 10 is a standard awareness document for developers and web application security. It represents a broad consensus about the most critical security risks to web applications. Understanding these vulnerabilities is the first step towards securing your applications.

1. Broken Access Control

Access control enforces policy such that users cannot act outside of their intended permissions. Failures lead to unauthorized information disclosure, modification, or destruction of all data. verify permissions for every request.

2. Cryptographic Failures

Previously known as Sensitive Data Exposure, this focuses on failures related to cryptography (or lack thereof). Use strong encryption for data at rest and in transit. Our Text Encryption Tool demonstrates basic encryption concepts.

3. Injection

Injection flaws, such as SQL, NoSQL, OS, and LDAP injection, occur when untrusted data is sent to an interpreter as part of a command or query. Validate all input and use parameterized queries.

4. Insecure Design

This is a new category for 2021, focusing on potential design flaws. It highlights the need for threat modeling and secure design patterns from the start of the project.

5. Security Misconfiguration

This is the most common issue. It includes insecure default configurations, incomplete or ad-hoc configurations, open cloud storage, misconfigured HTTP headers, and verbose error messages containing sensitive information.

6. Vulnerable and Outdated Components

Using components with known vulnerabilities is a major risk. You should regularly check your dependencies. Our CVE Search Tool helps you track known vulnerabilities.

7. Identification and Authentication Failures

These vulnerabilities allow attackers to compromise passwords, keys, or session tokens, or to exploit implementation flaws to assume other users' identities. Implement Multi-Factor Authentication (MFA) to mitigate this.

8. Software and Data Integrity Failures

This relates to code and infrastructure that does not protect against integrity violations. An example is an application relying on plugins, libraries, or modules from untrusted sources, repositories, or content delivery networks (CDNs).

9. Security Logging and Monitoring Failures

Insufficient logging and monitoring, coupled with missing or ineffective integration with incident response, allows attackers to further attack systems, maintain persistence, pivot to more systems, and tamper, extract, or destroy data.

10. Server-Side Request Forgery (SSRF)

SSRF flaws occur whenever a web application is fetching a remote resource without validating the user-supplied URL. It allows an attacker to coerce the application to send a crafted request to an unexpected destination.

Final Thoughts

Securing web applications is a continuous process. By keeping the OWASP Top 10 in mind during development and code reviews, you can significantly reduce the risk of security breaches.