Point : 100
When open it just nothing in the web page. So view source and see any information.
Haa! We got something in the javascript. There are some hex string. So we decode it, and got userAgent, substr, length, getElementbyId and etc..
So we try to understand what they are doing.
Basically, it just take the value from the userAgent, for example like this :
Mozilla/5.0 (Windows NT 6.1; WOW64; rv:39.0) Gecko/20100101 Firefox/39.0And then compare that value with plaintext value which is :
The supreme art of war is to subdue the enemy without fighting.So now if we change the userAgent value to that string, then we can proceed with the if statement here.
Then change the userAgent (User Agent Switcher for firefox) and you refresh the page and dont forget to edit the html page, because there is css element that will make it display nothing :
Just remove the "display:none" or you remove id="board" in the div tag. Then you will see a md5 hash string.
I dont know whether the md5 hash is the flag because I dont solve this challenge at that time. Haha.