hackthissite.org extbasic 2 :: Extension blocking
by Arxleol on Friday 25.12.2009, under hackthissite.org, php, tutorial
Second extended basic mission is somewhat simple. Let’s solve it 
In introduction:
You have this function, provide the value which must be POST-ed as filename to obtain the desired results:
Get the source code of hackthissite.org/index.php
here is the function:
We have to find vulnerability in the following code:
So we have to find way to see code of the file on server. From the source code we may see that file to be opened is created merging strings using the name of the file and extension. So we have to enter correct name in the box to see file. Basically correct name is index since .php will be attached later in function call.
Now the problem is to solve how to traverse us into the root directory. We will do this by putting ../../ in front of the index. Since ../ returns us one directory back.
Because if you try to put anything in the box you will obtain URL similar to the following one:
http://www.hackthissite.org/missions/extbasic/template.php?lvl=2&pass=
So you may notice that we are in the directory missions/extbasic/. Using ../ will return us two directories back to root directory.
So final combined solution is:
../../index
Wednesday 13.01.2010 on 02:56
uhm just found this youtube vid on youtube and a few people claim it works
Saturday 23.01.2010 on 20:15
Thanks for keeping your site up to date and working, we all know it costs you money and we appreciate all your money and hard work that you put into it