All PHP developers working with user-based content face similar challenges with security. What methods to take, how to avoid certain vulnerabilities, all these elements resulted in innovation of new security methods and techniques designed to fight against unintended loopholes in their code.
While sometimes remembering the basics can help, we discuss several different techniques to minimize security vulnerabilities that may arise otherwise.
Use Sanitization and Form Handlers
Sanitization handlers or form handlers are both great ways to performing basic sanitization for you automatically. They both are pass-throughs for retrieved data.
For example, by creating a form handler to handle your forms you can force the data incoming through some basic sanitization before you get the chance to manipulate it. It is like passing it through a checkpoint before ultimately reaching you, where you can perform additional sanitization.
Using this, you can at least assure yourself that the incoming user data from forms is somewhat sanitized before being sent to its final destination such as a database.
Sanitization handlers are also great. They can be used against superglobals, variables, and others to sanitize data before reaching you. It works just like form handlers but is more specific to data in general. Using this will also help create base-level sanitization so any information you forgot to sanitize is not left completely vulnerable, if at all.
Performing Front-End Tests
A lot of the times finding security vulnerabilities in your code is easier when performing tests on the front end rather than skimming through your code on the backend.
For example, if you have a form, you can perform thorough vulnerability tests against XXS attacks, SQL injections, and others. An attack succeeding on the front end indicates a security vulnerability on the backend that you may not easily find otherwise.
While performing these thorough vulnerability tests may take time manually, there are some great software out there that perform the tests for you in a quick and thorough fashion.
These two addons in specific perform the vulnerability tests you indicate for the fields you select. Once the tests have completed they return a list of vulnerabilities that have passed and or failed. A great way to perform some final tests before making your work live.
Many developers prefer frameworks, and they are definitely a great way to minimize on security vulnerabilities.
Some great PHP frameworks out there have well-developed sanitization methods and handlers, so in general, you would not have to worry about creating your own handler and breaking it down to specifics.
When using a framework, the core is essentially complete for you, and all you need to do is build upon it. This not only saves you the time and effort put into building one from the ground up but it also helps back you up in case you forgot to perform some basic sanitization on some data.
We definitely recommend either using a reliable framework already developed, or developing your own that is more specific to your projects and needs. This will definitely have your back when you unintentionally left incoming data unsanitized.
Database Handler Classes
A good method to handling data well when entering your database is to develop a handler class. With the handler class, you can become accustomed to it specifically which can help minimize many security vulnerabilities you may have missed otherwise.
The reason it can minimize on security vulnerabilities is that when developing your database handler class you can specifically develop it to, automatically pass the incoming data through some sanitization. There are a plethora of database handler classes out there that have specific methods noted as “prepare” queries, such as WordPress.
The prepare method within these classes are a method to perform the data sanitization for you before the query is actually executed. Doing this, allows the developer to be somewhat comfortable when sanitizing data as forgetting to sanitize some input will not do much harm if at all when passed through the prepare method first.
Unit testing is definitely a great way to test for security vulnerabilities, specifically related to permissions and restricted functionality. If you do not know, Unit Testing is a tool or method to use to perform tests on certain functionalities of code snippets, allowing you to easily test and know whether your code is functioning as it was designed or not.
It is especially a good tool and method to adapt to with big projects where you may not be able to test the functionality of certain code snippets without using big chunks of code.
So how does this help minimize certain security vulnerabilities? Due to the nature of Unit Testing, it can be used against several applications, which makes it a good candidate to test against code specific to certain user permissions within your script, as many security vulnerabilities occur because user permissions are not being strictly followed as developed.
By performing a unit test on sensitive code such as permissions, you can assure whether the code is properly working around the restrictions or not, which may not be noticeable otherwise.
Testing Your Code as You Develop
While testing your code as you develop seems like a basic thing to do, we have seen many developers not do it until they finish each code block as a whole.
The problem with completing each code block without performing tests on its sub-features is that when it comes to actually testing the code block as a whole, you may not notice vulnerabilities you may have otherwise. Additionally, when debugging your code, debugging an entire code block will take more effort than debugging small code snippets or sub features within it.
For example, if you are developing a method within a permissions class that performs several functionalities including account verification tests, you may not notice a faulty conditional statement without actually testing the method in small code snippets rather than as whole.
The reason is, when testing your method’s code as a whole, you may not reach that faulty conditional statement because of another unnoticeable error or the way the test is actually being performed. Therefore, always test your code as you develop it instead of completely developing, then testing.
Code and Method Consistency
While being basic, consistency of the code and method are both very important to minimizing security vulnerabilities. For example, inconsistent code can make it more difficult to read and work with which makes it very difficult to notice code or data that has been left unsanitized.
Additionally, inconsistent development methods create inefficient code that can confuse the developer, which can cause an increase in security vulnerabilities.
Therefore, when developing, always keep your method and your code consistent throughout each project.
To conclude, minimizing code vulnerabilities is all about continuing to follow a checklist of actions to perform while you develop for each code block.
Most of the techniques mentioned have been developed because developers felt the need of a system to rely upon for their sanitization or security needs when they forget to perform them.
Of course feel free to share your own tips and tricks in the comments below ;)