31st Jul 2008
PHP MySQL Injection Prevention
The number one security topic present in applications that use PHP is the SQL injection. This is because PHP allows for web developers to make unfortunate mistakes when it comes to creating their SQL queries. But thankfully, fixing the problem is easy: all that is necessary is a few tips in security.
An SQL injection attack is, simply put, a vulnerability in the SQL query that programmers unwittingly leave wide open. When a web developer calls an SQL query, he or she will commonly forget to escape quotes that the user might input. Users might input text such as “MyVariable’ OR 1=1–” ; this line will actually give the malicious user to your database!
As long as we can escape the quote that needs to be used in the injection, we can prevent any type of harm that may come to a web application. The first way to accomplish this is to simply use magic quotes. It should be noted that magic quotes are no longer supported as of PHP 6, and shouldn’t be used. Instead, we leave SQL injection prevention up to a newer and more dependable command.
Using the “mysql_real_escape_string()” function will enable web developers to escape quotes properly. And unlike magic quotes, this function will only escape quotes that we need. Keep in mind that when using this function, it may be necessary to use the “striplslashes()” function to counteract the slashes that are being outputted as a result.
Oddly enough, we can create a greater sense of security through creating more user accounts via our SQL program. We can assign different types of access to different users, which would make it quite hard for attackers to get full access to our database should they find a hole somewhere. Having a user for creating, deleting, and inserting data is a good idea to help split up responsibility.
It should be noted that programs and web applications that stop SQL injections should not be obtained- since they commonly cost quite a bit of money. As long as webmasters take precautions with what they create, there should be no reason to spend hundreds of dollars on software that only makes use of escape characters and formatting data correctly. This type of application is created to con webmasters into buying something they don’t need- so dont fall victim to them!
In Conclusion
There isn’t much effort that needs to be exerted in order to declare a database safe from harm. All that is needed is a little prevention- which comes from avid usage of the function and design principles previously stated. It may also be a good idea to use SQL injection scanners on large web applications to cover holes that might not have been covered over the course of the development period.
Learn more about Prevent SQL Injection and SQL Injection.
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