Tips for PHP Security
February 28, 2023

6 PHP Security Best Practices


Companies working with PHP are typically building or managing websites and web APIs. And, because websites and web applications are a common target for exploits, maintaining PHP security throughout the application lifecycle is hugely important to preventing potential exploits.

In this blog, we give our top PHP security best practices, including how to keep PHP application security top of mind when developing new features or maintaining applications, why it’s important to document your existing infrastructure, how to ensure your infrastructure is configured according to known security best practices, ensure PHP applications are patched against vulnerabilities, and why it’s important to train your teams to recognize and prevent security risks. 

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6 PHP Security Best Practices 

To create the most secure PHP websites and applications possible — and safeguard you and your customers’ sensitive data — start with these PHP security best practices. However, remember that these PHP application security best practices are just the tip of the iceberg when it comes to security. Your team should be constantly evaluating emerging threats and your susceptibility to them.

1. Always Code With Security in Mind

As developers, we tend to use varying tools (e.g. SAST tools) that we don’t fully understand and are under the stress of making a deadline where functionality takes precedence. The problem with this is that we end up introducing security flaws to our applications. 

Frameworks and libraries have helped a lot with those concerns, and using the elements provided by those frameworks properly greatly reduces the risk of attacks.

The obvious drawback is that frameworks themselves are sometimes vulnerable, and when a vulnerability is discovered in a framework, it affects the various applications written with it. It’s critical you know the tools you’re using and be aware of the OWASP top ten vulnerabilities and how to protect your applications against them. Some of the top concerns include:

  • Broken authentication: Flawed implementation of authentication and session management functions.
  • Cross-site scripting (XSS): Storage of untrusted data in a web application without sufficient validation.
  • Broken access control: Failure to enforce restricted user access of specific data.
  • CSRF: an attack that forces an end user to execute unwanted actions on a web application in which they're currently authenticated

The OWASP site offers the full list of risks and recommendations for prevention.

2. Understand and Document Your Existing Infrastructure

While this one may seem like a no-brainer, one of the biggest security risks for large companies is that they don’t know the full extent of their IT infrastructure – which makes it almost impossible to keep that IT infrastructure patched and secure. Without adequate mapping of their IT infrastructure, companies are likely deploying unpatched and/or end of life technologies (more on this in our fourth best practice).

This makes it important for companies to have a fully documented and regularly maintained software bill of materials that lists any technologies they deploy as part of their IT infrastructure. Maintaining this list makes it easy to quickly identify the components used in your applications, see the version they are running, and determine if they are vulnerable to new CVEs. 

3. Ensure Your PHP Infrastructure Is Properly Configured

Whatever patches and fixes you establish in your system, they won’t do much good if your infrastructure isn’t properly set up. Your infrastructure is likely made up of various tools, containers, load balancers, database servers, cache stores, and more. If they aren’t configured appropriately, if credentials are mismanaged, or if systems are not kept up to date, unauthorized users may gain access to restricted information and data exchanged between the networks could be compromised.

Setting up your network also involves being aware of threats and setting firewalls and other protective measures to minimize the likelihood of them coming to fruition. Some of the risks involve:

  • Unpatched security vulnerabilities
  • Lack of a comprehensive credential management strategy
  • Abuse of user account privileges
  • Lack of encryption

4. Maintain PHP Code

PHP is constantly being improved upon, and with each new version comes added security improvements. For this reason, it’s in your best interest to update to the latest version of PHP for your PHP security. Using an older version means you’ll stop receiving support over time — typically after three years — and you won’t be able to apply critical security patches and bug fixes to your application.  

As mentioned earlier, code written within PHP is inherently vulnerable; there is always a door for a hacker with enough time, money, and resources to find their way in. This means your code must be as bulletproof as possible. With version updates come required changes to your code that add layers of protection and reduce the chance of an attack.

For companies deploying or managing many PHP applications, this further stresses the importance of a regularly maintained software bill of materials. 

5. Educate and Train All Employees

While total prevention is impossible, understanding how your systems work and their vulnerabilities will allow you to not only mitigate them, but respond to any attacks that do occur before they become worse. Educate your team on common threats, as well as proper PHP development and deployment habits that will keep your web applications secure — not just today, but in the long term.    

Keeping data secure should be an organization-wide effort. After all, it’s not just technical attacks that can occur; social engineering can take place in various forms as well. Social engineering involves manipulation on the part of an attacker to gain access to confidential and sensitive information. Hackers may contact an employee outside of your IT department, via phone or email, to request access to certain internal materials by impersonating someone else. Through formal security training, you can educate all members of your staff on the appropriate actions to take in such situations. 

6. Ensure Your Teams Make Security a Top Priority

This last PHP security best practice might be the trickiest. Development teams across the world are asked to balance both the creation of new features/applications, and the maintenance of their existing applications. And, nearly without exception, most teams aren’t staffed to do both adequately.

results from 2024 php landscape report showing developer prioritization of building new features vs app maintenance

Source: 2024 PHP Landscape Report

Based on the data we’ve seen in recent PHP Landscape Reports, most teams are prioritizing new feature development over application security, which means that – from a leadership perspective – security starts and ends with making sure your teams have the time needed to address your PHP security objectives. 

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Frequently Asked PHP Security Questions

From a security standpoint, finding good information on PHP security-related questions can be hard. This section looks at a few of the more commonly asked questions for PHP security.

Is PHP Secure?

PHP is as secure as any other programming language. But, just like any other language, it requires programmers to write and engineer secure applications.

How Do I Protect a PHP File?

The method required for protecting a PHP file varies depending on the location and function of the PHP file. For basic file system protection, most servers allow developers to set permissions on a file by file, or directory-wide basis.

What Is SQL Injection in PHP?

SQL injection in PHP is a common code injection technique used to disable, or place malicious code within an SQL database. Because PHP applications frequently use SQL queries to interact with databases, PHP applications are at risk of SQL injection unless proper security measures are taken.

Which Is More Secure, PHP or Python?

No programming language is inherently secure. The argument for PHP security vs Python security, for example, largely boils down to language maturation. The bottom line is that application security is largely dependent on the code written for that application.

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Final Thoughts

While this list is a good starting point for teams who want to learn more about PHP security best practices, it’s far from comprehensive. Ultimately, PHP application security is an ongoing effort, and one that requires time, buy-in, and continued prioritization within your organization. Without that, maintaining security will necessitate working with a third party to ensure that security.

If your team needs help assessing the security of your PHP applications, Zend provides a security audit service that reviews your application for potential attack vectors, unpatched vulnerabilities, and then recommends steps to improve your overall application security. Also be sure to check out our PHP LTS offering, which provides patches and bug fixes for EOL PHP versions.

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Maintain PHP Security With PHP LTS From Zend 

Zend PHP LTS includes SLA-backed patches and bug fixes for EOL PHP versions. See what we offer by visiting our LTS solution page. 

See Our PHP LTS Options

Additional Resources

Editors Note: This blog first appeared on 12/19/2019. It has been substantially updated with additional content as of 2/28/2023.

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