Login as theblacksheep!
- Since the username is 'theblacksheep', just input it and submit.
- And the page will show us an error message like below:
Access Denied! Key Validation Error!
- Key?! Yes, there's a key using for authentication but must be hidden to us.
- After viewing the source code, we found that there isn't any hidden value in the form. Maybe we should check the details in HTTP Protocol.
- I use Chrome Developer Tools to do so. And we could discover that there's a suspicious field named 'userkey' in the HTTP header. Its value is 'd0p3fish|key|code'.
- Now, we need to intercept the HTTP packet and forge the header with a new field like 'userkey: d0p3fish|key|code'. There's a lot of applications and extensions could achieve our purpose. I choose Burp Suite, since it has a nice reputation for a long time and, of course, very easy to use.
[Reference] A nice introduction article about Burp Suite:
- Well done!