Try the challenge thoroughly before reading the write-up. Otherwise, it's your loss.
Recap of previous level.
The recap provides an alternate way of solving the challenge using a symlink(
ln -s /bin/sh uname) and changing the PATH environment variable to the current directory. It too was a really cool method.
The story of this level tells us that there is a service running on one of the ports(not given which). So we’ll have to do a bit of recon to figure out which port it is. Well, thankfully we have been provided with the nmap tool. Otherwise we might have had to write our own port scanner. While you are at it, do check this one that I wrote(not for the challenge though).
The range of the ports has been provided in the story to be 0x5ad to 0xdad, which is 1453 to 3501 in decimal. So, scanning this range for open ports using nmap:
Thus 2989 is an open port.
We then try to netcat into this open port, and are presented with the following
I had no idea what to make of this. So I followed their third hint and watched the movie: TRON Legacy :P. Also, I needed a break.
This is the part which is important though:
So we just do what Flynn did, and get level5 shell. Woot Woot!
We now have the flag to the next level. I am not revealing the password here so that the readers try the challenge on their own. It was a fun challenge overall, and the storyline seems to be getting pretty interesting :) .