Basic 9
I have found that is has something to do with NULL and how the search engine works, like in the POST variavle codes (if you know php you know what I am talking about), where the file search is, you have to put in something like ../(file you want to view in previous folder)%00. This is a common exploit that was used for cgi's (yuk!), even though the file may not permit you to access it, it will, because it thinks its a NULL command after it is executed (ie executing the command, without it knowing it is).
That is all this info I have gotten with the NULL commmand, and it hasnt seemed to help, but maybe it will help peice the puzzle togeather.
Which leaves us to the question of what unobtainable file do we need to get? I know the exploit you are talking about and it seems a bit logical for the mission, but I am not sure if this is the right direction.
When it says "cannot be injected by the url" it would make you think we would be using SQL injection, right?