NetSPI Blog

Karl Fosaaen

Karl specializes in network and web application penetration testing. Karl holds a BS in Computer Science from the University of Minnesota and has over a decade of consulting experience in the computer security industry. In that time, he has worked with a variety of industries; including financial services, health care, and retail. Karl holds the Security+, CISSP, and GXPN certifications. In his spare time, Karl has volunteered at conferences including DEF CON, THOTCON, and AppSec USA. Karl has previously spoken at BsidesPDX, THOTCON, AppSec California, and DerbyCon.

Karl Fosaaen
April 27th, 2015

GPU Cracking: Rebuilding the Box

A little over two years ago, we built our first GPU cracking box. At the time, there was pretty limited information on what people were doing to build a decent cracking box, especially if you were trying to do so without breaking the bank. As with any piece of technology, things go out of date, […]

Karl Fosaaen
March 2nd, 2015

NetSPI’s Top Cracked Passwords for 2014

It’s been a big year for password cracking at NetSPI. We’ve spent a lot of time refining our dictionaries and processes to more efficiently crack passwords. This has been a huge help during our pentests, as the cracked passwords have been the starting point for gaining access to systems and applications. While this blog focuses […]

Karl Fosaaen
December 15th, 2014

Cracking Stats for Q3 2014

During many of our penetration tests, we gather domain password hashes (with permission of the client) for offline cracking and analysis. This blog is a quick summary of the hashes that we attempted to crack in the third quarter of 2014 (and so far for this year). The plan is continue doing this again at […]

Karl Fosaaen
October 6th, 2014

LM Hash Cracking – Rainbow Tables vs GPU Brute Force

Lately, Eric Gruber and I have been speaking about the cracking box that we built at NetSPI. Every time we present, the same question always comes up. “What about Rainbow Tables?” Our standard response has been that we don’t need them anymore. I honestly haven’t needed (or heavily used) them for a while now, as […]

Karl Fosaaen
August 18th, 2014

Cracking Stats for Q2 2014

During many of our penetration tests, we gather domain password hashes (with permission of the client) for offline cracking and analysis. This blog is a quick summary of the hashes that we attempted to crack in the second quarter of 2014 (and so far for this year). The plan is to continue doing this each […]

Karl Fosaaen
June 9th, 2014

Malicious MobileConfigs

How much can you trust your devices? In this blog post, we will cover a practical attack that utilizes the iPhone Configuration Utility, a malicious Mobile Device Management (MDM) server, and a little bit of social engineering to get you data from iOS devices, HTTP and HTTPS web traffic, and possibly domain credentials. The Scenario: […]

Karl Fosaaen
June 2nd, 2014

Cracking Stats for Q1 2014

During many of our penetration tests, we gather domain password hashes (with permission of the client) for offline cracking and analysis. This blog is a quick summary of the hashes that we attempted to crack in the first quarter of 2014. The plan is to do this again each quarter for the rest of the […]

Karl Fosaaen
March 15th, 2014

GPU Password Cracking – Building a Better Methodology

In an attempt to speed up our password cracking process, we have run a number of tests to better match our guesses with the passwords that are being used by our clients. This is by no means a definitive cracking methodology, as it will probably change next month, but here’s a look at what worked […]

Karl Fosaaen
January 27th, 2014

ADA Requirements – Opening Doors for Everyone

This is a bit of a departure from our technical blogs, but today we’re going to show you how to build your own door opening tool out of hardware store materials. For those who are not familiar with a “lever opener tool”, it’s a tool used by locksmiths (and others) to open doors from the […]