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OSCP: more questions

2017-05-25 18:12:00

Here's another question I've had a few times, which came to me again this weekend:

"I'm really surprised you had the confidence to tackle the exam with just 19.

Is this you bread and butter ? Was this simply to formalize existing knowledge for you ?"

To be honest, I was just as surprised that I passed! No, I don't have workexperience in the field of pen-testing; I've only done two or three CTFs.

My original intention with my exam was to consider it a recon missions for my second exam. I was sure that 19 out of 55+ hosts was not enough to be prepared for the exam. I went into the exam fully reconciled with the idea that failing was not just an option, but all but assured. The exam would be a training mission, to learn what to expect. 

The day before my exam I had practiced exploiting a known buffer overflow in EasyRMtoMP3Converter (EXE). Here's the CoreLan writeup from 2009. Using the approach I learned during the PWK class and by studying various published exploits, I built my own Python script to exploit the software. After some additional work, the code worked against both Windows 7 and XP. 

This extra practice paid off, because I managed to finish the BOF part of the exam within two hours. This was basically the wind in my sails, what got me through the whole exam. After finishing the BOF I dared to hope that I might actually have a chance :) And I did. tags: , ,

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OSCP: Is the Pentesting With Kali (PWK) course worth it?

2017-05-23 14:07:00

One of my past colleagues reached out to me today, asking me this:

I'm still OSCP-wannaby, but probably it is too technical for me. I'm still not sure. Could you please share if a pre-exam training is worth its price or what is your practical - cutting of 'try harder' ;-) - advice to pass it?

I'll post my reply here, because I've been telling people this very thing for the past few weeks.

I've always thought OffSec's online PWK training to be well worth the money! $1150 gets you a huge PDF with all the course work, a few hours of videos and 90 days of lab access. It also includes your first exam attempt. For a training of this quality, that's really not a lot of money! You could even opt to pay even less, getting only 30/60 days of lab access.

The classroom variant is something else entirely though. It's a LOT more expensive, at roughly $6000. That's for a week's on-site training, including a CTF event on one night. You also get the same PDF and videos, the included exam, but only 30 days of lab access. For me, it was well worth it because it was five days of non-stop hacking in a room with 30 other students and two top-notch trainers.  

Something that saved me time and money: during the classroom training you receive the two most important VMs, which you can use on your OWN laptop. Thanks to that, I didn't have to start my lab access until I'd finished >90% of my exercises. In the online PWK you use lab access to work on your exercises!  

The course is always worth it before taking the exam: submitting a proper report of your coursework may net you 5 bonus points on the exam. Submitting a pen-test report for the labs may net you a further 5 bonus points. On a minimal passing score of 70, those 10 points can really help a lot!  

So yeah. Definitely work through all the coursework to get into it and score points. Then play a lot in the labs, for both practice and more points. Then take the exam when your time's up. Always do the exam! Because if you fail your exam and then renew your labs, OffSec will include a "free" retake of your exam with the new lab time! Totally worth it! That way your "failed" exam because a recon mission that teaches you a lot! tags: , ,

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Hooray for Google's free projects

2017-05-11 21:04:00

A few weeks ago, I reopened commenting on this site after having it locked behind logins for years. Since then the amount of spam submissions have been growing steadily. Sucks, so I finally took the time to implement proper spam checking. Enter Google's free project reCaptcha. Of course I realize that, if something's free on the web, it probably means that I'm the product being sold. I'll have to poke around the code to see what it actually does :)

CodexWorld have a great tutorial on getting reCaptcha to work in a basic script. Took me less than an hour to get it all set up! Lovely! tags: ,

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I love Microsoft's documentation!

2017-05-09 10:24:00

Four Windows servers on one laptop

A bit over a year ago I first started working with Microsoft's Active Directory, integrating it with BoKS Access Control. At the time, I was impressed by Windows Server 2012 and 2016 and the ease with which I could set up an AD forest with users. 

I'm now learning how to build a two-tier PKI infrastructure, after seeing them in action at various previous clients. I've been on the consuming end of PKI for years now and I thought it was time to really know how the other end works as well! I must say that I love Microsoft's generosity when it comes to documentation! Not only do they provide proper product docs, but they also have online tutorials in the form of TLGs: test lab guides. Using these, you can self-teach the basics of a subject, and then build up from there.

The 2012 Base TLG helps you build a basic AD forest of systems. I can follow it up with the two-tier PKI infrastructure TLG, which helps me set up an offline root CA, and an issuing CA, along with automatically enrolling any new systems in the networkt that need SSL certs. Awesome!

I'm similarly extatic about the performance of my Macbook Air. It's a tiny, super-portable system, but it still doesn't balk at running my usual applications plus four full-fledged Windows Server 2012 hosts. Nice!


Ammar Hasayen also did a nice write-up, which appears to be based upon the two-tier PKI TLG but which adds additional details.

Also, Microsoft also offer a third great resource, their MVA: Microsoft Virtual Academy. They also have a course on two-tier PKI with ADCS tags: , ,

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Learning Powershell? Mind your flags!

2017-05-09 08:54:00

I can't believe such a small, silly thing had me going for ten minutes!

When trying to retrieve a signed certificate from my ADCS rootCA, I kept getting a "file not found" error:

> certreq retrieve 2 .subCA.corp.contoso.com_subCA.crt
: The system cannot find the file specified. 0x80070002 (WIN32: 2)

Googling didn't lead to many results, but then I realized: Windows commands need to discern between variables and values, just like any OS. Doh! Forgot the minus!

>  certreq -retrieve 2 .subCA.corp.contoso.com_subCA.crt

Works just fine! tags: , ,

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PWK and OSCP: pointers and advise

2017-05-07 14:38:00

It's traditional to do a huge writeup after finishing the OSCP certification, but I'm not going to. People such as Dan Helton and Mike Czumak have done great jobs outlining the whole process of the course, the exercises, the labs and the exam. So I suggest you go and read their reviews. :)

In the mean time, here are the few things I would suggest to anyone undertaking PWK+OSCP. 

The day after finishing the exam was one of elation: I couldn't be more happier. But not a day later, I'm already missing the grueling work! I want to go back to the labs, to finish the remaining 30+ servers I hadn't cracked yet. I even want to retake the exam, to get more challenges! 

For now, my plan is as follows:

  1. First, I'm going to study to upgrade my RHCSA and RHCE to RHEL7.
  2. When I'm between assignments again, I will invest in more PWK labtime to practice with more target hosts. 
  3. Once I have finished the labs I will continue my journey with OffSec's CTP (Cracking The Perimeter) course and the OCSE exam. 

Back in college, René was right: "That guy just doesn't know the meaning of the word 'relaxation'." tags: , ,

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She's a pass.

2017-05-04 17:28:00

I just received the official word from OffSec: I made it through my OSCP certification! As Dredd said: "She's a pass." tags: ,

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OSCP exam: done and dusted

2017-05-03 15:34:00

Sorry for posting in Dutch :) This is an ad verbatim quote from a forum post I made today; just a braindump of how my past day went. 

Wie is er gaar? Ik is er gaar! /o/

Ik heb m'n OSCP examen achter de rug! Dat ging eigenlijk een heel stuk beter dan verwacht :D

Het liefste was ik gisteren rond 0700-0800 begonnen, maar het vroegste timeslot dat ze je bieden is vanaf 1100. Ik had dus van 1100 gisteren tot zo'n 4 uur geleden de tijd voor het aanvallen van mijn doelwitten. Daar naast had ik van 1100 vanochtend tot morgen 1100 de tijd om mijn testrapport op te stellen en in te leveren. NOU! Het is een hele slag geweest, maar het zit er op. Ik ben uiteindelijk zo'n 21 uur in touw geweest.

M'n taktiek was om op de achtergrond een berg scans af te trappen, zodat ik me bezig kon houden met de bak waar geen scan voor nodig was: de buffer overflow oefening. Rond middernacht had ik in principe genoeg punten binnen om te slagen, dus bedtijd!

Maar helaasch :D Ik kon door de adrenaline de slaap niet vatten! Om 0200 er weer uit gegaan en verder gegaan. Rond 0300 ging ik m'n eindrapport vast opstellen. Om half zeven was die zo'n beetje klaar! Ik heb nog wat tijd gestoken in die laatste privesc, maar niets meer gevonden. Ik was om half negen zo gaar, dat ik't best vond! Ik heb al m'n documentatie verzameld, nog één keer alles goed nagekeken en ingezonden. 

Douchen en instorten! Geslapen tot een uur of elf en voel me nu al een stuk beter! :)

Ik had helemaal niet verwacht dat ik zo ver zou komen! Tussen alle verhalen op de OffSec forums, van mensen die helemaal dichtslaan en mijn eigen ervaringen uit het verleden, had ik niet verwacht meer dan één bak te kraken. Maar met wat ik heb bereikt heb ik an sich al genoeg punten om te slagen en ik hoop natuurlijk ook op de 5+5 bonuspunten voor de lab rapporten die ik indien. 

De ontvangstbevestiging van OffSec is in elk geval binnen. Nu begint het wachten! tags: ,

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OSCP exam: almost done

2017-05-03 06:41:00

4.5 hours left on the clock and I have four hosts fully rooted, the fifth I have a lowpriv shell. With the last one I decided to fsck-it and use the MSF Exploit, to save time :) I could've done it manually, but that would've cost me dear time. 

I didn't get any sleep because I was so strung out on adrenaline :D So after going to bed at 0015, I got up again at 0200. Got my foot in the door with the fifth host, then started writing my final report. Preparation and proper note taking works! In roughly 3.5 hours I have my report fully typed up! 

I can now investigate that last privesc at a leisurely pace :) tags: ,

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