Thoughts on PWK/OSCP Course

This year I wanted to improve my security knowledge and understand how an attacker would approach compromising an application so I could better secure solutions I was involved in developing.

I suspect most developers (including myself) learn about security from a mainly theoretical perspective and wont be exposed to an attackers methodology, tools or techniques. I think this is probably a mistake and most of us would benefit from seeing or having hands on (legal!) experience so we can build more resilient and secure applications.

I wasn’t sure where the best place to start with this was but my manager Horay had previously suggested that certifications in addition to providing proof of knowledge can be a good option by providing a learning path to work through. They also ensure you cover some areas that you might not cover on your own.

I had a look at what was available in the security cert space and there were a few options. Previously I’d chatted with one of my colleagues (hello Vats!) some time ago about Offensive Security’s Penetration Testing with Kali Linux course. This course concludes with a 24hr exam where you have to compromise a number of machines and then another 24hrs to write up how you did it and I was kind of intrigued by this.

The PWK is a self-study course aims to introduce you to penetration testing methodology, key tools and approaches. I understand this qualification is well respected in the industry due to the tough nature of the test and is currently pretty much essential for those wanting to start a pen testing career.

The course
The course costs start at $999 USD at the time of writing. This gives you 1 month’s lab access, 850 page PDF, a set of videos and access to their forums. It’s not cheap but I don’t think its unaffordable either and cheaper than your average multi-day conference. I felt overall it was good value for the money although I’ve listed some cheaper options at the end of the article.

Probably one of the best things about this course is the lab. You connect to the course lab using OpenVPN and it’s made up of an extensive set of machines (70ish) and connected networks all waiting for you to compromise them. I don’t want to spoil any surprises as participants will enjoy the details but I will say that a lot of thought has gone into the setup of this and its not just 70 separate machines..

One thing you should be aware of and that creates some pressure is that when you enrol in the course you have to select a date to start. Your lab time will then start ticking down from this date so make sure you have cleared some time in your schedule as this course will consume substantial time..

How long is enough lab time?
Unless you are studying this course full time (how good would that be?) or have prior security experience and are doing this for the certification most folks will need 2 or 3 months lab time at least. From what I read multiple extensions and exam retakes are common.

I enrolled in the course with 2 months lab access. I work full time in a demanding job and am a single parent with 2 little kids and I worked on the course mostly once the kids were in bed or at weekends. I made it through the book & exercises and compromised about 16 machines in the lab and another 10 or so on Hack the Box (more about this later). This was fun but exhausting and I’m not sure I’d recommend this pace. If you can do get more lab time – you wont regret it.

You can extend your lab time afterwards but it is more expensive to extend than upfront (currently $359 USD for 30 days). There are also other cheaper practice machine options but we’ll get to that.

Pre-Req Knowledge
To make the most of the course you will need to have knowledge in 4 main areas:

  • Networking (basic stuff – DNS, TCP/IP basics, ports etc)
  • Linux (intermediate?)
  • Windows (basic)
  • Programming (basic and comfortable modifying Python & Bash scripts. I’d rarely worked with Python but it was trivial to make the basic mods necessary during the course e.g. setting variables, basic logic)

For those of you starting out in IT I probably wouldn’t recommend this course as a starting point and guess you’d get frustrated pretty quick. Even if you know you want a pen testing career you’ll probably get more from it with a few years dev or infra experience. Having said that I did read some blog posts from a few folks who had jumped right in and had success so each to their own I guess.

I think most folks coming to this course unless they are coming from the security world already will find they have at least one weak area in the above. For me it was limited Linux experience and knowledge although this was offset by a software development background and understanding of web applications. An unexpected benefit I found was that by the end of the course I had a good working knowledge of Linux and loved working with it 😊

What I enjoyed
I really enjoyed this course and loved the range of subjects and areas it covered.

I think this was probably the most fun course I have ever done and you get a genuine rush when compromising one of the lab machines which was er weirdly addictive and led to some late nights as I worked through a tricky problem.

By the end of the course, you will have a decent understanding of the methodology pen testers (and I guess also attackers) will approach compromising a machine and network.

This gave me a new perspective on development projects and will assist with the development of secure software.

For me the highlights of the course were:

  • Compromising my first lab machine. I cannot stress enough that the lab and most of the exercises are really fun, time will fly and it doesn’t feel like work
  • Whilst I was familiar with the concepts of subjects like buffer overflows it’s a different thing altogether to create one yourself and having it initiate a reverse shell 🙂
  • I was surprised at how sophisticated some of the common tools were and how easy they made tasks e.g. MetaSploit & SQLMap
  • Playing with assembly – cant think of when I have done this outside of uni!
  • SSH tunnelling – wow didnt know you could do some of this stuff!
  • Abusing various inbuilt Windows and Linux functions to do things like download a file from a remote machine using regsvr, certutil etc

What I wish I had known
Offensive Security have a motto “Try Harder” that you’ll come across this many times in the course materials and forums.

I can imagine that pen testers require resilience and perseverance and if you are not the sort of person who will get curious about a problem and work through it then you probably wont enjoy this course or pen testing for that matter. However, let’s remember you are doing this course to learn and there is a point where “Try Harder” is not useful (“Bean dad” anyone?).

You have limited lab time and want to make the most of this. Whilst you can and will learn something researching a challenging topic there’s a point where you are probably better off getting some help. In this course help will come mainly from the forums.

At the beginning of the course I got stuck on a machine for nearly a week. Whilst I learnt stuff trying to work through this issue I probably should have looked at the forums earlier to learn a concept I wasn’t aware of. I also would have found this wasn’t one of the best machines to begin with. When you start you also want something matching your skill and experience level so you can practice the basics without getting frustrated and not getting anywhere. My advice would be to set a time limit and then look at the forums if you are stuck to help you get past the blockage then continue on your own.

Offensive Security provide a lab learning path of machines they suggest you work through. I didn’t spot this at the beginning even through its on the lab machine control page doh. This has 10 or so machines to work through with the first 2 having a detailed step by step write-ups in the forums. Do look at this as you’ll learn a lot especially with the first 2 writeup’s!  

The machines are of varying difficulty and by the end I could exploit 2-3 in one night with I think the quickest being 15 or so minutes and the longest a week (at the beginning of the course!).

For most machines you’ll run a port scan and maybe some other scans and then work through the various services. It took me a while to realise this but its very easy to get stuck thinking one option is certain to be the route in. This is a trap! Set a time limit for each service/hole and then work through them systematically. You will be amazed what you missed when come back round or what you might discover on another service you haven’t looked at yet.

For me I mostly found I could get a foot hold on most machines fairly easily but the challenges came around privilege escalation.

Privilege escalation is where you have some kind of access to a machine but it is of a limited level and you then attempt to increase this access. There’s various ways of doing this from exploiting misconfigured setups and binaries to full on kernel exploits. As a beginner I found this area the hardest and had to grind through all the options which could be tiring and frustrating but worth persevering with.

Tib3rius has two really great privilege escalation courses on Udemy (one for Linux and one for Windows) which I wish I’d watched earlier in the course and would highly recommend.

Conclusion
I haven’t taken the exam for this course yet (that’s in a couple of months as I wanted a break over xmas period and need to get some practice in!) so cant comment on that aspect yet (you’ll find a heap of posts around others experiences). I will say however that really enjoyed this course and learnt a lot from it so would highly recommend it. It also had the unexpected benefit for me of massively upgrading my Linux skills 🙂

Alternatives/Supplements
For those folks not caring about the OSCP Certification or wanting a cheaper option Heath Adams’s (the Cyber Mentor) Practical Ethical Hacking course is amazing value at AUD $10.99 for over 24hrs content.
This covers much of the same areas as PWK and is really well put together (I also think the Windows AD stuff in examined in more depth).

Other Resources
Now it should go without saying that trying to compromise machines you don’t have permission to do so is illegal and shouldn’t be done under any circumstances.

There are several great and free/cheap services offering legal and great options to practice against that can help you prepare for the course:

Hack the box has many machines to practice against and some are similar to those on the course. If you’ve never done this stuff before however do not start here as you’ll get frustrated quickly as there is little to no guidance provided. I’d recommend the paid version of the service as it gives you access to older machines that have detailed write-ups if you get stuck.

TryHackMe have many “rooms” that take you through the development of various skills and experiences e.g. specific tools and techniques. If you are not sure if this stuff is for you then the recent Advent of Cyber room is a really nice basic intro to some basic techniques:

IppSec YouTube Channel. IppSec provides video walkthroughs of hacking various (mainly HackTheBox) machines. This guy is a genius and entertaining to watch. I’d watch a few videos each week and found I would learn heaps and come across some great tools and techniques.

Linux Smart Enum. This script makes it really easy to see Linux privesc options more than the better known LinPEAS and LinEnum. Highly recommend adding to your toolkit.