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Wednesday, March 27, 2013

Tips to Create Secure PHP Applications

PHP is one of the most popular programming languages for the web. Such languages are very helpful for the programmer but the security holes in it can create a problem. They can create problems in the development path.Below are few tips to help you avoid some common PHP security pitfalls and development bug.
1. Use of Proper Error Reporting
Error reporting can be your best friend during the development process. Error reports helps you to find spelling mistakes in your variables and also detect incorrect function usage. Always make sure that you hide all the error reporting once you decide to make the site live.
This can be done by invoking the simple function “error_reporting(0)” at the top of your application file(s).
You should always make sure to log your errors to a protected file. Which help to detect the problem when something go wrong. Therefore, This can be done with the PHP function “set_error_handler”.
2. Disable PHP’s harmful Features
PHP’s creators have always included some features to make PHP development easier. Some of these helpful features can have unintended consequences.
We can call these as “bad features” because they have allowed data validation and created a path for bugs to finding their way into scripts. One of
the first things you should do when the development process begins is
disable certain of these features. Depending on the host which you are using, these may or may not be turned off for you. If you are developing on your own computer or any local environment, they probably won’t be turned off. Some of these features have also been removed in the upcoming PHP6, but are ubiquitous in PHP4 applications and are only deprecated in PHP5 applications.
3. Validate Input
With addition to escaping characters, another good way to protect
input is to validate it. Normally you actually know what kind of data you are expecting on input.  So the simplest way to protect yourself against attacks is to make sure your users can only enter the appropriate data.
4. Watch for Cross Site Scripting (XSS) Attacks in User Input
A web application usually accepts input from users and displays it
in some way. They can be in a wide variety of forms. When accepting input, allowing HTML can be a dangerous thing,because that allows for JavaScript to be executed in unintended ways. If even one hole is left open, JavasScript can be executed and cookies could be hijacked. This cookie data could then be used to fake a real account and give an illegal user access to the website’s data. There are a some ways you can protect your site from such attacks. One way is to disallow HTML altogether, because then there is no possible way to allow any JavaScript to execute.
5. Protecting against SQL Injection
SQL injection attacks occur when data is not checked, and the application doesn’t escape characters used in SQL strings such as single quotes (‘) or double quotes (“). If these characters are not filtered out users can disturb the system by making queries always true and which allow them to trick  login systems.
MySQLi help protect your database input. We can do it in 2 ways.
Either with the mysqli_real_escape_string function when connected to a server or with prepared statements.
Prepared statements are a method of separating SQL logic from the data being passed to it. The functions used within the MySQLi library filter the input for us when we bind variables to the prepared statement.

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