Becoming Security Aware

The Register published an interesting article yesterday describing how a website owned by the Department for Homeland security was compromised.

The attack used a directory traversal vulnerability. This attack allows the attacker to access files and directories outside of the applications web root folder.

The full details are in The Register article along with further comment from Paul Ducklin from Sophos.

What I found most surprising however was my own reaction as a read the article. The attack revolves around a URL of of the form:

that the attacker then abuses to give following form: 

Note: the directory path of the file.

As soon as I read the first URL form it was obvious how the attack could be executed, if the ‘download.php’ did not adequately validate the file name. Identifying where the is a problem is the first step in being able to find a solution.

I can only describe my reaction is as a result of becoming much more security aware. Previously I would have looked at the URL and thought little or nothing off it. Now, it leaps out of the screen as something evil. A threat and an attack vector that needs to be closed. It acts as a warning to ensure that the ‘download.php’ script is carefully code reviewed. It acts as a trigger to generate evil use cases that can be used to test the behaviour of the script.

The more others have a similar reaction to myself, the more difficult we make the job of the attacker. That can only be good for all web users.