Wed, Jan 06, 21
Welcome back to my walkthrough of hackthissite.org’s CTF missions. I will be going through my thought process of how I solved these missions, and therefore also giving away the solutions. If you came across this to give you hints, watch out for spoilers! Good luck, have fun.
We have graduated out of the basic missions, and are stepping into the realistic missions. This first challenge that we’ve been presented with asks us to bring up a band to the top of a voting list - that band being Raging Inferno.
After going to the website, I can see a selection of 5 different bands that are organized in order of their average rating. The top band somehow has a rating of > 23 even though you can leave a vote ranging from 1-5. Examining the forms we can see that different bands are given their own id, the same phpsessid, and a choice of a vote ranging from 1-5. The request is also done through a get request.
I will record what the request looks like by sending a vote for our favorite band - Raging Inferno - by using the network tab on google chrome dev tools. This vote is sent through a GET request to the following URL: www.hackthissite.org/missions/realistic/1/v.php, with the following query parameters: PHPSESSID=abcaeadfc31a5c43b2534bf995c0553f&id=3&vote=5.
The first thing that we should attempt is to try and send a request but set vote to some astornimical number like 10 million and see if the vote parameter is properly remediated. So our URL will look like the following: www.hackthissite.org/missions/realistic/1/v.php?PHPSESSID=abcaeadfc31a5c43b2534bf995c0553f&id=3&vote=10000000.
This has redirected us back to hackthissite saying that we have completed the mission! I guess we brought our favorite band up to the top.