OSCP Week 15: Mock Exam (HackTheBox Part 3)

I initially thought that my exam was going to be the Friday just gone, but I quickly realized I had underestimated how much time I had, and found myself with another week to prepare for the OSCP exam.

After some thought about what I should do with this newfound time, I decided to set myself up with a ‘mock exam’ in an attempt to create an environment that will be as close to the actual thing as possible. I decided to do this for 2 reasons:

1. Gain some more confidence attempting machines on my own under a time restraint.
2. Hammer home the importance of taking regular breaks and drinking/eating properly throughout an extended period of time at the computer.

The entire OSCP exam spans 24 hours, and with 5 machines in total you are essentially given a little less than 5 hours per machine. To recreate this on a smaller scale, I decided to attempt 3 active HackTheBox machines in 8 hours. This gives approximately 2.5 hours per machine, much less time than what the OSCP exam provides per machine. However, I think it balances out because the longer length of the OSCP exam makes the later stages significantly harder both mentally and physically. Having a stricter time pressure for a shorter “exam” made sense, as this way I could put the pressure on right from the start.

I then selected the 3 machines I would be attempting on the HackTheBox network. After some consideration, I decided to go for the following:

1. “Help” – Linux, Easy difficulty
2. “Carrier” – Linux, Not Too Easy difficulty
3. “Netmon” – Windows, Piece of Cake difficulty

I decided to go for these 3 machines in particular for the following reasons:

1. I wanted a mixture of both Linux and Windows machines
2. I didn’t want them to be over “Medium” difficulty – I’ve seen people report that the OSCP exam machines tend to not go past the “Medium” difficulty on HackTheBox.
3. I wanted them to be less “CTF-Like” and more “Real Life”. HackTheBox has different rating scales for each machine, and I decided to prioritize the machines that were rated more “Real Life”, as Offensive Security have also tried to create their machines to resemble those you might see in “Real Life”.

Based on the difficulty scale, I’d say that these machines are likely to be of similar difficulty to the two 20 point machines, and the one 10 point machine.

So, on Sunday morning I woke up early and started to crack into these 3 machines. After a much more difficult 8 hours than I had expected, I obtained 1 root and 1 low privilege shell. In all honesty, I was a little disappointed. I was hoping for at least 2 roots, so only being able to achieve 1 in the total time I spent was a hard pill to swallow.

However, I do feel as though I learned a lot, and got a feel for how difficult the real exam is going to be on Friday. More than anything, I realized that I let myself get burnt out in the second half of this mock exam, and I now understand that I need to force myself to take regular breaks in the early stages. It’s not enough to just sit back and drink some water for a couple of minutes, I will really need to get up from my desk and do something else. Ideally, it would be useful if I walk around to clear my head and get some fresh air, even if I don’t think I need it at the time. The mental block will inevitably hit, and it will hit hard.

Ultimately, I wasn’t too disappointed with my performance in this mock exam. I was satisfied at my perseverance throughout the day, and the progress I was able to make was a useful barometer for my current level. Although I wasn’t quite successful this time around, the real thing is still to come and that’s where it will matter the most.

See you all next time for my post-exam write up.

Kento.