OverTheWire Natas Level 8 Walkthrough

Today we're doing a walkthrough of level 8 of the Natas CTF wargame hosted at: http://natas8.natas.labs.overthewire.org In order to access the level, we will need to authenticate into the webpage by providing the current level of the game as the username (natas8) and the password we obtained from the previous level as the password. After we've authenticated into the page, we see this: It looks like we will need to provide the form with the right string to get the password for the next level. Let's take a look at the sourcecode link in the corner: http://natas8.natas.labs.overthewire.org/index-source.html According to the source code, the $encodedSecret string is transformed by the encodeSecret function, and if the string we submit to the form matches the transformed $encodedSecret, then the password for natas9 will be displayed. The $encodedSecret is first encoded into base64, then the string is reversed, and the reversed string is converted from binary to hex format. So,...