Securing PHP Applications: Best Practices

We are living in 2025, and hardly a day goes by without the news that another business or venture has been aggressively hit or compromised due to an unwanted security breach. Tech has multiple sides, it can be a boon or a bane, both good and bad, sometimes it can do ample right, whereas other times it can inverse impact as well. Today, the time has come for security, especially for your websites and applications, must be taken into account right from the beginning and not as an afterthought. More or less, it has become a pure necessity.

It doesn’t matter what website or app you have come up with; what matters the most is that it is highly secure. I mean, who would consider staying on an insecure website? Would you? Of course not! Not to mention that an insecure website has the potential to not just leak all the sensitive information but also user data to a great extent. And in the end, no matter how many years you have spent on building a company image, everything will go into the ashes and put a permanent dent in the trustworthiness of the website. Are you ready to mess this up? Since the stakes are high, you need to come up with a sure-shot solution, such as choosing or relying on the most amazing and prominent, or should I call a veteran technology? Yes, I am talking about none other than our very own PHP. So the following post is about to enlighten you regarding why you need to choose PHP and what the top PHP security best practices are to consider for a successful development project.

About PHP

PHP is considered one of the most widely used programming languages available on the web. No wonder it has the potential to power millions and millions of websites, ranging from the smallest blogs to large and highly functioning eCommerce platforms. Irrespective of your choice of the development project, PHP remains relevant in the present as well as the future. Did you know that the tech powers more than 80% of all websites, which means it is ten times more popular than ASP.NET. Here’s why!

• PHP is an open-source technology

• PHP excels in security

• Short learning curve

• It offers great performance

• Versatile and easy to get started with

• Highly compatible

• Amazing in terms of scalability

• SEO-friendly

• Amazing range of databases featuring relational databases such as MySQL, PostgreSQL, and SQLite, and NoSQL

• Frequent updates

• Easily adaptable to the current trends

• Cross-platform compatibility, especially with most web technologies

• Lastly, it comprises a huge community of active and experienced programmers who are happy to help whenever in need.

Now, despite all these advantages, PHP is considered pretty much notorious for its wide range of security vulnerabilities. One of the main reasons here is due to its perception, you see, since this one is older and open source technology, hackers find it extremely easy to exploit poorly written apps, and these exploits have gained notoriety. Which is why we need to consider some of the best PHP security practices. We assure you that by following these practices, PHP is the best choice when it comes to web development projects.

Why is there a need to secure a PHP website?

PHP is a server-side language that assists well in developing a high-quality dynamic range of websites across the globe. As mentioned earlier, the tech is open-source, which means quite available for free, enabling programmers of irrespective experience levels to customize the website from any nook and cranny. However, unfortunately, the open-source nature makes it one of the easiest targets for hackers. So, in simple words, not securing the PHP website can result in severe consequences such as the bad guys gaining unnecessary unauthorized access, stealing and misusing sensitive data, and even taking full control of the website. In the end, you will be doomed with a compromised website resulting in data breaches, damage to reputation, and ultimate loss of customers’ trust. In the worst-case scenarios, all the legal liabilities and financial losses can be exposed in no time. And Google will surely blacklist you which can have a huge impact on the business as a whole.

Before spotting the remedy, time to spot the top PHP security issues or cybersecurity threats.

Top PHP Security Issues

XSS

Cross-Site Scripting, commonly known as XSS, is the most common type of attack that is found among web applications all across the globe. Now, these are basically one of the most amazing forms of injection attack, not in a good way, of course!

Now, XSS is mainly inserted in a website in the form of a hyperlink or a web form. This inserted code is mainly used with the assistance of any client-side language, be it JavaScript, PHP, or HTML.

Most of the time, such XSS attacks are bound to happen on vulnerable websites that accept user input with the help of a GET parameter, and the data is successfully displayed on the website.

Here is an example:

https://example.com/profile/?u=john

The URL mainly points to a website that successfully reads the value for username from the URL.

So, what does an attacker do? He simply injects malicious code into the website by setting the value for u.

https://example.com/profile/?u=alert("Your website is compromised!")

No matter how trivial this seems, attackers tend to use such unnecessary procedures to send the unassuming user to a site they control.

In simple words, XSS attacks are conducted to inject malicious scripts within your website, allowing hackers to hijack different user sessions, steal cookies, and access the most sensitive and confidential data.

However, there is a solution here:

• Validate and sanitize all the user input to successfully remove all the malicious code

• Successfully implement a web application firewall to detect and block XSS attempts.

• SQL Injection

The next issue with PHP websites on a usual basis is SQL injection, also known as SQL. This issue generally occurs when attackers tend to exploit different vulnerabilities within the code and succeed in executing different malicious SQL commands on the database.

So here, the hacker simply wants to access all the usernames and passwords present in the database.

As a solution:

• Try using well-prepared statements and input validation

• This will surely sanitize the user input

• Make sure to successfully implement all the stored procedures

• Do not forget to deploy WAF, especially to monitor and block SQL injection attempts

• Remote File Instructions

The next issue that needs to be considered with a PHP development project is remote file instructions. The RFI vulnerability is another interesting issue that successfully enables attackers to feature or incorporate different remote files located on the server, so what these files do they simply grant the bad guys easy access to every kind of sensitive information and allow them to have complete control over the website.

As a solution:

• Try avoiding the overuse of arbitrary user input

• Also, make sure to implement input filters to successfully sanitize different parameters in comparison to different file inclusions

• Make sure to deploy a WAF to successfully detect and block numerous RFI attempts.

• Cross-Site Request Forgery

The next kind of massive issue that can hamper your well-developed PHP website is cross-site request forgery. This kind of attack mainly tricks end users into performing unintended actions on the website, let’s say changing the password or making unauthorized transactions.

As a solution:

• Try using anti-CSRF tokens, which can surely validate numerous requests

• Implement the same site cookie policies

• Of course, make sure to conduct security audits and vulnerability assessments regularly.

• Session Hijacking

Last but certainly not least type of issue often found among websites is the session hijacking. Here, attackers are able to steal user session cookies, and they are the ones who tend to grant unauthorized access to the user accounts and data.

As a solution:

• Expiring session cookies upon logout and generating new ones on login.

• Implementing secure cookie handling and session management practices

So now, it’s time to focus on the solution! Yes, down below, I would like to mention some of the best PHP security best practices to take into account.

PHP Security Best Practices

Regular PHP Updating

One of the best practices that needs to be taken into account is making sure updating PHP to the latest version. This is the prime thing to do when it comes to enhancing security and addressing vulnerabilities. With each new release, you are bound to receive proper bug fixes as well as security patches, especially for the known issues, and by doing so, you are safeguarding the app against all potential attacks.

Here, several tools need to be taken into account, such as PHP Versions Manager (PVM), PHP FPM, as well as hosting control panels, which assist well in streamlining the update process. Here’s a step-by-step guide:

• First, begin by backing up the files. Do not forget to back up the database as well

• Second, do not forget to check compatibility, especially with third-party libraries and frameworks.

• Make sure to test updates before deploying to the live server

• As mentioned above, use the most preferred tool, such as PVM, PHP FPM, or a control panel, and update PHP on the server.

• Make sure to test thoroughly and monitor in case of any errors, especially after updating.

Overall, updating regularly is a must. This is how you can deliver a highly secure, bug-free, and amazingly smooth user experience. This is how you can successfully protect the website from unusual threats and vulnerabilities.

Code Reviewing

The next best practice that needs to be considered is code reviewing. This practice is all about choosing dedicated PHP developers via proper examination of the codebase and watching out for all the potential security issues. What are these issues? Well, improper input validation, insecure database queries, weak authentication mechanisms, and the list goes on.

Some of the most useful tools to consider in code reviewing include:

• Using different code review platforms, which can Phabricator, Gerrit, and GitHub Pull Requests.

• Different version control systems: Git, SVN, Mercurial

• Static code analysis tools such as PHP Code Sniffer, RIPS, and Phan

Certain steps for effective code reviews

• Establish clear guidelines and coding standards

• Allocating proper dedicated time for thorough reviews

• Absolutely encourage collaboration and constructive feedback

• Leveraging proper code review tools for streamlining the processes

• Constant improvement of the review process, depending on feedback

  User input validation

  Now, this aspect can be your absolute gatekeeper of the developed application. User input validation is extremely needed in preventing relevant vulnerabilities such as SQL injection and XSS attacks involving absolute validation and sanitization of different user inputs, even before the app is processed.

Some of the most amazing built-in functions offered for validation by PHP include:

• Filter_input() and filter_var() for validating based on predefined filters

• Htmlspecialchars() and htmlentities() for escaping and encoding special characters

How to secure user input validation?

• Identifying all input sources - forms, URLS, cookies, headers

• Validating and sanitising input with the help of different PHP filtering functions or custom rules

• Escaping and encoding different outputs before displaying to prevent XSS

• Implementing whitelist validation, especially for those that are only known-safe inputs

• Make sure to set reasonable length limits, especially for input fields

• Log and keep a hawk eye on user input in case of any attack attempts.

  Using SSL certification for HTTPS

The next best practice to take into account is the usage of SSL certifications, especially for HTTPS.

Usually, SSL certificates and HTTPS offer seamless encryption for relevant data transmission between clients as well as servers, which prevents interception and ensures to establishment of absolute and highly secure communication. Some of the potential advantages to consider here include:

• Great data encryption to protect all sensitive information

• Server authentication for seamless verification of the website’s identity

• Make use of different certificate authorities, such as DigiCert, Comodo, and Let’s Encrypt, to obtain proper SSL certificates

• Use relevant web server configurations, such as Apache, Nginx, to enable SSL and HTTPS

• Certbot, WHMCS for proper certificate management and renewals

How to implement SSL certificates?

1. Make sure to choose a trusted CA to obtain relevant SSL certificates

2. Configure the web server to use these certificates

3. Update website URLs and use “https://” for all resources

4. Try implementing redirects from HTTP to HTTPS

5. Renew certificates periodically before expiration

Try implementing SSL/HTTPS with valid certificates to encrypt data, authenticate your website, comply with regulations, and enhance trustworthiness and search rankings.

Encryption and hashing

Last but certainly not least, one is encryption and hashing. This is usually done to protect some of the most sensitive data featuring information regarding passwords, credit cards, and more. This method is used to protect data in the most unreadable format. At the same time, hashing generates irreversible fixed-length values for data integrity and authentication. This is what PHP offers:

• openssl and mcrypt for encryption algorithms like AES

• password_hash() and password_verify() for secure password hashing (bcrypt, Argon2)

Certain steps for securing encryption and hashing:

• Using some of the strongest algorithms, such as AES for encryption and bcrypt/Argon2 for hashing

• Managing different encryption keys in a pretty secure manner and making sure to separate them from the data

• Do not forget to use hash passwords with password_hash(), and make sure it isn’t in the form of plain text

• Always make sure to verify hashes using `password_verify() and do not try comparing manually.

• Use some random salts with the password, and make sure to do this before hashing

• Store all encrypted data and hashes securely; all of this needs to be done with restricted access.

  Conclusion

And we are done for now! Conducting your upcoming development project using PHP is the best choice, just make sure you follow all the aforementioned strategies and practices.

Safety is much better than being sorry, and in this cut-throat, competitive world, being sorry is not an option. So brace yourself, time to give your best shot!

I hope you did find the following post worth taking into account. In case you have doubts or any queries, feel free to mention them in the comment section below. We will surely reach you as soon as possible. Good luck with your upcoming development project.