Understanding Web Vulnerabilities

Introduction

Web vulnerabilities are weaknesses in web applications that attackers can exploit to gain unauthorized access or perform unauthorized actions. Understanding these vulnerabilities is crucial for developing secure applications. This lesson focuses on the OWASP Top 10, a comprehensive list of the most critical web application security risks.

OWASP Top 10 Overview

The OWASP Top 10 is a standard for the most critical web application security risks. It is updated regularly to reflect the current threat landscape. Here are the ten categories:

1. Injection
2. Broken Authentication
3. Sensitive Data Exposure
4. XML External Entities (XXE)
5. Broken Access Control
6. Security Misconfiguration
7. Cross-Site Scripting (XSS)
8. Insecure Deserialization
9. Using Components with Known Vulnerabilities
10. Insufficient Logging & Monitoring

Vulnerability Categories

1. Injection

Injection flaws, such as SQL injection, occur when untrusted data is sent to an interpreter as part of a command or query. This can allow attackers to execute arbitrary commands.

SELECT * FROM users WHERE username = 'user' AND password = 'pass';
            

In the example above, if user input is not properly sanitized, an attacker could manipulate the SQL statement.

2. Broken Authentication

This vulnerability occurs when application functions related to authentication and session management are not implemented correctly.

3. Sensitive Data Exposure

Applications must protect sensitive data, such as credit card numbers and health records, to prevent unauthorized access.

4. XML External Entities (XXE)

XXE vulnerabilities occur when an application processes XML input from untrusted sources.

5. Broken Access Control

Restrictions on what authenticated users can do are often not properly enforced.

6. Security Misconfiguration

Default configurations, incomplete setups, and missing security headers can lead to vulnerabilities.

7. Cross-Site Scripting (XSS)

XSS vulnerabilities allow attackers to inject malicious scripts into content from otherwise trusted websites.

8. Insecure Deserialization

Insecure deserialization can lead to remote code execution if an attacker can manipulate serialized objects.

9. Using Components with Known Vulnerabilities

Applications using outdated or vulnerable components can be compromised easily.

10. Insufficient Logging & Monitoring

Failure to log and monitor can allow attackers to maintain persistence and perform unauthorized actions without detection.

Best Practices

To mitigate web vulnerabilities, consider the following best practices:

• Implement input validation and output encoding.
• Use prepared statements for database queries.
• Regularly update software and libraries.
• Enforce strong authentication and session management.
• Implement proper access controls.
• Conduct regular security audits and penetration testing.