Initially I signed up for this track thinking it was Linux. Just before the competition, the track name was changed to Unix, meaning Mac. Luckily I was able to use a Mac, though I have never programmed or reversed on one. This and the next few challenges were quite the learning experience. I eventually (level 6) wound up purchasing Hopper from hopperapp.com. It is a great tool for debugging on Mac and Linux, though I'll probably continue to find use for IDAfree on Linux. Unlike the free IDA, Hopper includes a disassembler that helps some with code analysis.
This was more of just a logic/hunch test in my case. I ran soconnect.sh and Wireshark to see what types of network activity were going on, and all that happend was a page request from example.com. I ran strings and found reference to y2k and 01/01/1999, then thought maybe the challenge required that the server return a date near the y2k roll date. I modified /etc/hosts to redirect www.example.com to a VM, set the data in the VM to December 10, 1999 and ran the test. Got the password. I chose 12/10/1999 just kind of by chance, as I wrote a script that would set the date, wait for a keypress, then increment the date at the server. I just started at 10 and was going to work my way up. Turns out, I didn't need to.
On the server:
for i in $(seq 10 31); do sudo date --set=1999-12-$i;sed -n q </dev/tty;done
On the client: