PHP is one of the most popular programming languages in use today. It is used by millions of websites, including some of the biggest names on the internet. While PHP is a very powerful language, it can also be quite insecure if not used properly. In this blog post, we will discuss 11 best practices for PHP security that will help keep your website safe from hackers and malicious users. We will also talk about the application pen testing and how to use it to find vulnerabilities in your code.

How does application pen testing help businesses?

Application pen testing is a process of identifying vulnerabilities in software by simulating an attack on the system. This type of testing can be used to find flaws in the code that could allow attackers to gain access to sensitive data or take over the website. 

The most common flaws identified during application penetration tests relate to lack of secure coding practices, misconfiguration vulnerabilities, broken authentication and access controls and information leakages. These are only the top flaws, including but not limited to OWASP top 10 risks. By running regular application pen tests, you can find and fix these vulnerabilities before they are exploited by hackers.

11 best practices for PHP security

1. Always use the latest version of PHP

New versions of PHP are released regularly with security fixes and improvements. By using the latest version, you’ll have the benefit of these fixes and improvements as well as any new features that might be helpful for your website.

2. Use Up to date code dependencies and third party components  

In addition to using the latest version of PHP, you should also keep your code up to date. This includes any third-party libraries or frameworks that you’re using. Outdated software is often the target of attacks because hackers know that it is more likely to have vulnerabilities that can be exploited.

3. Secure your web server

Your web server should be configured properly to protect your website from attacks. This includes ensuring that all unnecessary services are disabled and that file permissions are set correctly. You should also use a firewall to block unwanted traffic and an intrusion detection/prevention system (IDS/IPS) to monitor for suspicious activity.

4. Do not store passwords using reversible encryption

There are a few key reasons why reversible encryption is harmful. First, it can easily be cracked and decrypted, making your data vulnerable to theft or exposure. Second, it can be used to spy on or track your activities, since the encryption and decryption process leaves a clear trail of activity. Finally, it can be used to enumerate all other user passwords also given there is a static key in use for encryption and decryption process. 

Instead, you should hash the passwords with a strong hashing algorithm like bcrypt or Argonaut. Outputs prepared using hashing algorithms are less vulnerable to attacks than encryption algorithms. This makes them more secure for storing passwords or other sensitive data due to the sheer computing power required to find clear-text (decryption) equivalents. Additionally, hashing algorithms are much faster than encryption algorithms, making them better suited for use in applications where speed is important.

5. Don’t rely on cookies for security

Cookies are often used to store information about users, such as their login status, username, preferences or even sensitive information. However, cookies are not inherently secure and can be easily stolen by attackers. If you need to store sensitive data in a cookie, you should encrypt it first.

6. Validate user input

All user input should be validated before it is processed by your PHP code. This includes data entered into form fields, URL parameters, and JSON payloads. By validating user input, you can help prevent Cross-Site Scripting (XSS) attacks and other types of malicious input.

7. Use allowlists (formerly whitelists) instead of blocklists (blacklists)

A blacklist is a list of items that are not allowed, while a whitelist is a list of items that are allowed. When using blacklists, you have to be careful not to allow any unauthorized items through. Whitelists are much safer because they only allow authorized items. You should always use whitelists whenever possible.

8. Restrict access to sensitive files

Certain files on your web server should be restricted to only trusted users. These files could include the configuration file, database credentials, or source code files. By restricting access to these files, you can help prevent attackers from gaining access to sensitive information.

9. Ensure that error messages are not revealing

Error messages can often give attackers clues about how to exploit your website. For example, if an attacker tries to access a restricted page, they might see an error message that says “Access denied”. To prevent this, you should ensure that error messages are not revealing and do not contain any sensitive information.

10. Use SSL/TLS

SSL/TLS is a secure protocol that can be used to encrypt traffic between your web server and the user’s browser. This helps protect against man-in-the-middle attacks and other forms of eavesdropping. You should always use SSL/TLS when transmitting sensitive information, such as passwords or credit card numbers.

11. Perform regular security audits

Regular security audits can help identify vulnerabilities in your website and fix them before they can be exploited by attackers. By auditing your code, you can also ensure that it is up to date and follows best practices for PHP security.

Conclusion

Following these best practices will help you secure your PHP applications and protect them from attack. Remember to always keep your software up to date, use a firewall and IDS/IPS, and validate user input. And be sure to perform regular security audits to identify any vulnerabilities that may have slipped through the cracks.