PHPUnit tests for key features like authentication and input validation

Oct 13, 2025 by miodeya.com 74 views

As a developer, maintaining a secure and high-quality codebase is crucial for the success of any project. However, many projects often overlook essential security measures and best practices, leaving them vulnerable to attacks and errors. In this article, we will discuss the common security and code quality issues found in many projects and provide suggested fixes to improve their overall security and maintainability.

1. Insecure Password Hashing (MD5 Usage)

One of the most critical security issues in many projects is the use of insecure password hashing algorithms like MD5. MD5 is not secure and is vulnerable to collisions, making it easy for attackers to guess or crack passwords. To improve password security, we recommend using password_hash() for storing passwords and password_verify() for authentication.

Why is MD5 insecure?

MD5 is a non-cryptographic hash function, making it easy to find collisions.
MD5 is not designed to be secure for password storage.
MD5 is vulnerable to rainbow table attacks.

How to fix MD5 usage?

Use password_hash() to store passwords securely.
Use password_verify() to authenticate users securely.

2. Lack of Prepared Statements (SQL Injection Risk)

Another common security issue in many projects is the lack of prepared statements, making them susceptible to SQL injection attacks. Directly concatenating user input into SQL queries is a recipe for disaster, as it allows attackers to inject malicious SQL code. To prevent SQL injection attacks, we recommend using prepared statements with mysqli_stmt_bind_param().

Why is SQL injection a risk?

SQL injection allows attackers to inject malicious SQL code.
SQL injection can lead to data breaches and unauthorized access.
SQL injection can cause system crashes and downtime.

How to fix SQL injection?

Use prepared statements to separate user input from SQL queries.
Use mysqli_stmt_bind_param() to bind user input to prepared statements.

3. No Proper Input Validation & Sanitization

Proper input validation and sanitization are essential for preventing cross-site scripting (XSS) attacks and invalid data. User inputs are not properly validated or sanitized, leaving the system open to XSS attacks and invalid data. To improve input validation and sanitization, we recommend using filter_var() for email validation and htmlspecialchars() to sanitize inputs.

Why is input validation important?

Input validation prevents XSS attacks and invalid data.
Input validation ensures data consistency and accuracy.
Input validation improves system security and reliability.

How to fix input validation?

Use filter_var() to validate email addresses.
Use htmlspecialchars() to sanitize user inputs.

4. Weak Session Management

Weak session management can lead to session fixation or session hijacking. Sessions are not properly managed, which can cause security risks. To improve session management, we recommend using session_regenerate_id(true) after login and implementing proper session timeout handling.

Why is session management important?

Session management prevents session fixation and hijacking.
Session management ensures user authentication and authorization.
Session management improves system security and reliability.

How to fix session management?

Use session_regenerate_id(true) to regenerate session IDs after login.
Implement proper session timeout handling to prevent session fixation.

5. Poor Error Handling

Poor error handling can expose sensitive database information and cause system crashes. Errors are being displayed directly with die(), which can expose sensitive database information. To improve error handling, we recommend using try-catch blocks for better error handling and logging errors instead of displaying them to users.

Why is error handling important?

Error handling prevents sensitive database information exposure.
Error handling ensures system reliability and uptime.
Error handling improves user experience and security.

How to fix error handling?

Use try-catch blocks to catch and handle errors.
Log errors instead of displaying them to users.

6. No Separation of Front-End & Back-End Logic

Mixing front-end and back-end logic in one file makes the code harder to maintain and debug. Separating front-end and back-end logic is essential for better organization and maintainability. To improve code organization, we recommend using a separate config file for database connections and implementing MVC (Model-View-Controller) architecture.

Why is separation of logic important?

Separation of logic improves code organization and maintainability.
Separation of logic ensures better debugging and troubleshooting.
Separation of logic improves system scalability and reliability.

How to fix separation of logic?

Use a separate config file for database connections.
Implement MVC (Model-View-Controller) architecture for better organization.

7. No Unit Testing

Lack of unit testing can lead to critical functionality failures and bugs. The project lacks unit tests to verify critical functionality (e.g., login, registration). To improve code quality and reliability, we recommend adding PHPUnit tests for key features like authentication and input validation.

Why is unit testing important?

Unit testing ensures code quality and reliability.
Unit testing prevents critical functionality failures and bugs.
Unit testing improves system scalability and maintainability.

How to fix unit testing?

Add PHPUnit tests for key features like authentication and input validation.
Use PHPUnit assertions to verify expected behavior.

8. Lack of Code Documentation

Lack of code documentation can make it difficult for new contributors to understand the codebase. The code has minimal comments, making it difficult for new contributors to understand. To improve code documentation, we recommend adding proper inline comments and a README.md update explaining code structure.

Why is code documentation important?

Code documentation improves code readability and maintainability.
Code documentation ensures new contributors can understand the codebase.
Code documentation improves system scalability and reliability.

How to fix code documentation?

Add proper inline comments to explain code logic.
Update README.md to explain code structure and organization.

Suggested Fixes

To improve security and code quality, we recommend the following fixes:

Replace md5() with password_hash() and password_verify().
Use prepared statements for all SQL queries.
Implement input validation & sanitization before database interactions.
Improve session management to prevent security risks.
Implement proper error handling (avoid exposing database errors).
Separate front-end and back-end logic for better maintainability.
Add unit tests for authentication and form validation.
Improve code documentation to help new contributors.

In our previous article, we discussed the common security and code quality issues found in many projects and provided suggested fixes to improve their overall security and maintainability. In this Q&A article, we will answer some frequently asked questions related to security and code quality improvements.

Q: What is the most critical security issue in many projects?

A: The most critical security issue in many projects is the use of insecure password hashing algorithms like MD5. MD5 is not secure and is vulnerable to collisions, making it easy for attackers to guess or crack passwords.

Q: Why is SQL injection a risk?

A: SQL injection is a risk because it allows attackers to inject malicious SQL code into the database, which can lead to data breaches and unauthorized access. SQL injection can also cause system crashes and downtime.

Q: How can I prevent SQL injection attacks?

A: To prevent SQL injection attacks, you can use prepared statements with mysqli_stmt_bind_param() to separate user input from SQL queries. You can also use parameterized queries or ORM (Object-Relational Mapping) tools to prevent SQL injection.

Q: What is the difference between input validation and sanitization?

A: Input validation is the process of checking user input to ensure it meets certain criteria, such as email address or phone number format. Input sanitization is the process of removing or filtering out malicious input, such as SQL code or JavaScript code.

Q: Why is session management important?

A: Session management is important because it prevents session fixation and hijacking. Session fixation occurs when an attacker fixes a session ID to a specific user, allowing them to access the user's session. Session hijacking occurs when an attacker steals a user's session ID and uses it to access the user's session.

Q: How can I improve session management?

A: To improve session management, you can use session_regenerate_id(true) to regenerate session IDs after login. You can also implement proper session timeout handling to prevent session fixation.

Q: What is the difference between error handling and exception handling?

A: Error handling is the process of catching and handling errors that occur during the execution of a program. Exception handling is the process of catching and handling exceptions that occur during the execution of a program.

Q: Why is code documentation important?

A: Code documentation is important because it improves code readability and maintainability. Code documentation ensures that new contributors can understand the codebase and makes it easier to debug and troubleshoot issues.

Q: How can I improve code documentation?

A: To improve code documentation, you can add proper inline comments to explain code logic. You can also update README.md to explain code structure and organization.

Q: What is the most important thing to remember when it comes to security and code quality?

A: The most important thing to remember when it comes to security and code quality is to always prioritize security and maintainability. This means using secure coding practices, following best practices, and regularly testing and reviewing your code.

Q: How can I get started with improving my code's security and maintainability?

A: To get started with improving your code's security and maintainability, you can start by identifying areas of your code that need improvement. You can then research and implement secure coding practices, such as using prepared statements and input validation. You can also use tools and frameworks to help you improve your code's security and maintainability.

Q: What resources are available to help me improve my code's security and maintainability?

A: There are many resources available to help you improve your code's security and maintainability, including online tutorials, documentation, and communities. You can also consult with security experts and developers who have experience with secure coding practices.

Conclusion

Improving your code's security and maintainability is an ongoing process that requires regular effort and attention. By following best practices, using secure coding practices, and regularly testing and reviewing your code, you can improve your code's security and maintainability and ensure a better user experience. Remember to always prioritize security and maintainability, and don't be afraid to ask for help when you need it.