A very overlooked part of PHP security is file uploading. A quick for instance. Lets say that you have a file uploader in which there is no security applied. Any file may be uploaded to the server. What if someone uploads a file that has a little extension by the name of ‘.php’? All that needs to be done now is in the file write a little script with ‘fopen’ and read all the files and echo them out to the browser. Now we have all the source code (maybe even usernames/passwords if we’re lucky) to the entire application. Not only that, but now we can write sql code to get all the data we want from the database. Then we could get really mean and update the database with some malicious javascript and have it download viruses or trojans on all the users computers who visit the website. Now google checks your website, realizes something bad is going on and decides to blacklist your website. Now mr. user comes along to your website, and he’s using firefox. Firefox checks with google to see if its ok to visit the website, google says ‘noooo’, firefox puts up a really scary red screen with a hand and an exclamation point and mr. user gets scared and decides never to come to this ‘bad’ site again. Then russia decides to launch ‘nucular’ missiles and we’re back in the cold war…. ok,, maybe not that last part but pretty much all the stuff before ‘nucular’ missiles I’ve experienced happening. So how do we stop the madness??

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_{Updated on 01/22/2009} There is no such thing as a 100% secure anything in this world of hackers/counter hackers. Especially when it comes to the world of web development. One of the many methods hackers use to infiltrate web applications is through session fixation. Session fixation is a way that hackers can use to gain unauthorized access to another users login. So how do we guard against this?

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