The PHP programming language has become one of the most efficient web development tools available. First introduced in 1994, this language has literally been used to create millions of websites throughout the world. While PHP offers the ability to create dynamic web pages and can be configured to run in a secure fashion, many of today’s servers are configured in a manner that leaves these scripts quite vulnerable.
Most servers running PHP are configured with the mod_php module as well as the Apache server application itself. This enables HTTP requests to be sent through the PHP engine, which is responsible for processing the request before data is sent to the client. Although this configuration offers a simple and effective way to get PHP functioning, it also raises security issues, especially in a shared or virtual private server hosting environment.
With the Masses Comes Massive Risk
Rarely will you find a company hosting one site on a single server. Because many personal and small business sites only require a fraction of the server’s resources, web hosting providers generally host a number of sites on a single machine. Though certainly more affordable than a dedicated server account, shared hosting offers numerous security risks. Some of these vulnerabilities exist because an HTTP server such as Microsoft IIS or Apache require a significant amount of control over the content served to the client. So if your website applications give visitors the ability to upload files or input data into web forms, you are essentially at risk as the HTTP server needs to have permission to write to a particular directory.
In the average shared hosting environment, the HTTP server is granted write permission to directories, giving anyone using PHP scripts on the server to write to directories as well. This is an issue that puts shared hosting customers at the mercy of their neighbors. Fortunately, there are a few preventive measures that can be taken to minimize these security risks, strategies that can be employed by both the server administrator and the end-user.
If you are hosting your site on a shared server configured with PHP, there are a few things that need to be done to remain isolated from common dangers. One of the easiest ways to prevent the exploits in your applications is to perform a sanity check. This simply means that if you require a user to enter alphanumeric characters, you need to make sure that is what you get instead of just letters or numbers. Additionally, you should never allow direct SQL queries without validation first, which requires the proper configuration of your databases as well. If your applications are not properly configured, you could easily be the victim of an SQL injection or similar exploits.
Allowing people to upload files to your site is risky, yet often necessary in some cases. Since PHP allows you to obtain information on uploaded files before they are written to a final destination, you should take of advantage of this privilege and make sure everything is in order. A common hacker exploit involves uploading malicious PHP scripts to gain access to sensitive files. A simple way to validate file types is to ensure that they are what you anticipate. For instance, if you only allow files that end in jpeg., anything else should strike you as suspicious.
All programming scripts have their vulnerabilities and PHP is one of the most widely exploited. You can enjoy all this amazing development tool as to offer by understanding the permissions on the host server and designing your site with security in mind.