System Overlord

A blog about security engineering, research, and general hacking.

Attacker Community DEF CON 26 Badge

I’ve spent an unhealthy amount of time over the past 6 months or so participating in the craze that is #badgelife. This year, I built badges for my Security Research Group/CTF Team: Attacker Community. (Because community is important when you’re attacking things.) Like last year, all of my badges were designed, assembled, and programmed by me. There are 24 badges this year, each featuring 8 characters of 14-segment display goodness and bluetooth connectivity. I may not be one of the big names in #badgelife, but if you just make some badges for your friends, there’s a lot less pressure in case something comes up.

Hacker Summer Camp 2018: Cyberwar?

I actually thought I was done with the pre-con portion of my Hacker Summer Camp blog post series, but it turns out that people wanted to know more about “the most dangerous network in the world”. Specifically, I got questions about how to protect yourself in this hostile environment, like whether people should bring a burner device, how to avoid getting hacked, what to do after the con, etc.

The Network

So, is it “the most dangerous network in the world”? Well, there’s probably some truth to that in the sense that in terms of density of threats, it’s likely fairly high. In terms of sheer volume of threats, the open internet is obviously going to be a leader.

First off, the DEF CON network is really multiple networks. There’s the open WiFi, which is undeniably the Wild West of computers, and there’s the DEF CON “secure” network, which uses WPA2-Enterprise (802.1x) with certificates to verify the APs. The secure network also features client isolation. Additionally, the secure network is monitored by a dedicated NOC/SOC with some very talented and hard-working individuals. I would assert that being compromised on the secure network is approximately the same risk as being compromised on any internet connection.

So, there’s 0-day flying around left and right? Not so much. Most of the malicious traffic is likely coming from someone who just learned how to use Metasploit or just found out about some cool tool in a talk or workshop. Consequently, it’s unlikely to have much impact for those who patch and are security-aware.

What you will see a ton of is WiFi pineapples. People will go buy one at the Hak5 booth, and then immediately turn it on and try to mess with other attendees. It gets pretty old, pretty quickly. Just make sure you’re connected to the DEF CON Secure WiFi and this will be a minimal problem (maybe a denial of service).

In all honesty, the con hotel WiFi is a worse place to be than DEF CON secure, by a large margin. Plenty of stupid things happening there.

3 Approaches

The Minimalist

The minimalist carries a flip phone with a burner SIM. He/she maintains contact with friends using SMS or (gasp) actual phone calls. No laptop, no smart phone to be compromised. This is a great approach if you’re not going to participate in any activities that require tech on hand. If you’re going to hang out, listen to a few talks, and drink, this is the approach with no need to worry about getting compromised.

The Burner

No, this isn’t about Burning Man, although DEF CON is kinda like Burning Man for “400-lb hackers in basements”. This hacker brings a burner version of everything: so a smart phone, but a cheap burner. This probably will get compromised, as their carrier hasn’t pushed a patch in 3 years. (And even before that, it shipped with some shady pre-installed apps that send all your contacts over plaintext to a server in China…). They also bring a $200 Dell or HP laptop with Kali Linux on board.

They connect to the first WiFi they see, never mind that it’s labeled “FBI Surveillance Van 404”. If you plan for your hardware to get pwned, it doesn’t really matter if it’s bad WiFi, right?

Of course, in order for this to work correctly, you have to never use your devices for anything sensitive. Hopefully the urge to check your real email doesn’t get too strong. Or maybe your card is suspended for potentially fraudulent activity (like that $300 SDR) and you decide to log in “briefly” to reactivate it. This route really only works if you can maintain good OpSec.

“Good Enough” Security

If you can set aside ego and assume nobody is willing to try using a $100k+ O-day on you, you can get by with a reasonable level of security. This involves bringing a modern fully-patched phone (iPhone or “flagship” Android phone), and optionally a well-secured laptop.

For the laptop, I’ve previously discussed using a Chromebook. Even with dev mode for crouton, I believe this to be reasonably safe from remote exploitation. This can also be cheap enough to be a disposable device. In my previous post, I suggested 3 Chromebook options:

Alternatively, you can get a cheap laptop and run fully-updated Windows 10 or Linux with a firewall enabled and be in a pretty good state for passive attacks over the network.

In either case, you should then run a VPN. I like Private Internet Access, but there’s a lot of options out there, or you can even run your own OpenVPN server if you’re feeling adventurous.


There’s never a guarantee of security, but with updated devices & good security hygiene, you can survive the DEF CON networks. The basic elements involved are:

  • Fully updated OS
  • Be super careful
  • Use a VPN
  • No Services Exposed

Good luck and see you at Hacker Summer Camp!

Hacker Summer Camp 2018: Last Minute Tips

This is an update to my planning guide as we get closer to Hacker Summer Camp. (We’re down to about 3 weeks now!)

Planning Your Time

Schedules and details for events have begun to be released. For example, we have:

It’s time to take a look at the lists of events and times and start making your “must do” list. Resist the temptation to try to plan every minute – first, you won’t be able to stick to it, and secondly, you’ll feel like it doesn’t leave you time for spur of the moment events. There will be conversations you want to have, people you want to meet, or unscheduled activities you want to check out.

For your evening plans, there’s no better source than the DEFCON Parties Calendar. Make sure you hydrate (and maybe take a shower) before you head out for the evening. Some of my favorites from years past include:

Dining & Restaurants

Value Eats

There’s a number of cheap eats in Las Vegas. I covered some of the cheapest in my first post, but I wanted to add a few more notes. I’ll focus on the ones in relatively close proximity to the DEF CON hotels (Flamingo and Caesars) as well as BSidesLV. I’ll also include things whose portion size/quality make up for the (slight) cost.

Quick bites (fast food):

  • Earl of Sandwich
  • Shake Shack
  • Caesar’s Food Court

Fast casual dining (sit down):


Buffets on the strip are not cheap, despite what you might have heard. They also can have long lines at dinner time, so don’t expect it to be quick in and out.

  • Caesar’s Palace is home to the Bacchanal Buffet, which has incredibly high quality options (and is one of the top-rated buffets in Vegas), but is a pretty expensive meal. The lines are likely to be very bad during DEF CON, so I suggest going to another hotel if you’re absolutely looking for a buffet.

  • Flamingo’s Paradise Garden Buffet is a middle-of-the-road buffet, with decent, but not outstanding food. It is dramatically cheaper than at Caesar’s, so might be a good option for all-you-can-eat at a lower price.

  • Next door to Caesar’s is the Mirage, which hosts a buffet named Cravings. Unlike many Vegas buffets, beverages here are self-service,so you’ll never be wanting for a drink refill, but also don’t expect many servers around. I haven’t been here myself, but the menus generally look unimpressive.

  • Though not particularly close by, the Wicked Spoon is one of the best regarded buffets in Las Vegas, with gourmet dishes made from the best ingredients. They also offer brunch 7 days a week, which appeals to some.

  • The Buffet at the Wynn (literally, it’s named “The Buffet”) has one of the best dessert/pastry selections along with great entrees and sides. It’s also not cheap, but will not suffer from the peak rush at Caesars.

Nicer Options

These are the kind of restaurants where you’ll want more than a t-shirt and jeans (and almost certainly no shorts)! Reservations are recommended. Vegas is full of these restaurants, but a few of my favorites include:

Top Shelf

Okay, to be honest, I don’t really do the top shelf restaurants myself. If you’re into that sort of thing, you might want to check out the usual guides (Michelin, etc.)

A few I’m familiar with:

  • Bouchon
  • Mon Ami Gabi
  • Restaurant Guy Savoy
  • Nobu

Packing Reminders

Handling the Weather

It’s going to be hot, so be prepared. I strongly encourage bringing a reusable water bottle like the aluminum bottle I’ll be sporting, or a Nalgene bottle. Some will even go with a bladder-style backpack. I’ll also bring along a cooling towel, which work surprisingly well! (They use evaporation to cool you down.)

Hacking All the Things

Maybe you’re into hacking and would like to give it a shot while at DEF CON. There’s a bunch of different options here. If you want to bring a laptop with maximum security, I can’t encourage bringing a Chromebook enough. At the budget end of the spectrum, I really like the Acer Chromebook 11. For a mid-range Chromebook, I like the C302CA. At the top end, there’s nothing quite like the Pixelbook, which is currently 25% off.

While you can get lots of tech in the vendor area, you might want to consider bringing a C232HM universal cable, or at least a UART Cable. This will at least get you basic capabilties to play around with any electronic badges you might come across.

If you’re into other specific activities (SDR, etc.), you’ll want to bring the appropriate gear.


It’s time to start making your day-to-day plans. Many have suggested leaving lots of room for flexibility and just going with the flow, which is not a bad idea at all. Have fun!

On Deep Work

I recently stumbled upon Azeria’s blog post The Importance of Deep Work & The 30-hour Method For Learning a New Skill, and it seriously struck a chord with me. Over the past year or so, I’ve struggled with a lack of personal satisfaction in my life and my work. I tried various things to address the issue, but could not figure out a root cause until I read her article, and then it clicked with me.

Even though I was constantly busy at work, I never felt like I was getting the things done that mattered to me: security research, tackling difficult technical challenges, focused security work. Instead I was constantly in meetings, switching tasks, dealing with email, and other work that felt like I was just barely keeping afloat at the office.

I’ve since read Cal Newport’s Deep Work: Rules for Focused Success in a Distracted World, and now I have an understanding of why I’ve had these feelings and, much more importantly, what to do about them. I’ll start by saying that the book is not one I ever thought I would be reading. It sounds like, and is, half self-help book and half business strategy book, neither of which are categories I usually give much attention. But Newport is also a professor of Computer Science, the book was recommended by Azeria, and I felt like I needed to try something different, so I gave it a shot.

The first third of the book is spent defining “deep work” and “shallow work” and convincing you that it’s worth pursuing “deep work”. I nearly gave up on the book at this point because my unhappiness with how things were already going had already convinced me of the value of deep work, so I figured I didn’t need a book to tell me I was doing things wrong, but I stuck with it, and I think it ended up being worth it.

Deep work is creative work that produces new value and requires that your stretch your brain to its limits. It is also the work that is best done in a state of flow (uninterrupted work focused entirely on one task at hand), and is the work that helps to build and grow the pathways in the brain. In my case, deep work includes things like security research, tool building, and learning new skills.

Shallow work is work that doesn’t require the full use of your brain, or that can be easily interrupted and resumed later, such as logistical tasks. In my case, this includes “doing email”, most meetings, and a lot of the collaboration I do with team mates. This is not to dismiss shallow work as unimportant, but it is different and done with a different mindset. It is also easier to get to shallow work with less mental friction, which leads to a tendency to go to shallow work.

All of this discussion is useless to me if I don’t actually make some changes based on what I’ve learned. I also don’t expect the “deep work” mindset to be a silver bullet to fix the problems I’m having. Some of the sources are likely outside that position, and going “all in” on the four rules set out by Newport would be difficult in my current corporate culture.

I am going to try some things though:

  • Schedule at least 3 blocks of 3+ hours a week for Deep Work. During this time period, I will not check email, respond to (or read) instant messages, etc.
  • Reduce the frequency with which I check email to ~3 times per day.
  • Use separate browser windows for deep work, so I can hide the windows that have the distractions.
  • Schedule time for personal projects as deep work.

Some problems I’ll still have:

  • My team works in a highly collaborative fashion. Realtime communication is expected. I’ll need to find some way to sequester myself.
  • I work in an open office floorplan, which has so many distractions that even shallow work is difficult. Finding somewhere to hide and do “deep work” means sacrificing my desktop and it’s large screens.
  • A corporate culture where anyone can schedule a meeting anytime and expect you to show up.

I’m going to try an increased effort on deep work and following some of the principles from the book, as well as better efforts to track how I spend my time. I’ll report back in 6 months time on whether or not I feel more productive, am happier with my work, and have actually been able to stick to these things.

Pros vs Joes CTF: The Evolution of Blue Teams

Pros v Joes CTF is a CTF that holds a special place in my heart. Over the years, I’ve moved from playing in the 1st CTF as a day-of pickup player (signing up at the conference) to a Blue Team Pro, to core CTF staff. It’s been an exciting journey, and Red Teaming there is about the only role I haven’t held. (Which is somewhat ironic given that my day job is a red team lead.) As Blue teams have just formed, and I’m not currently attached to any single team, I wanted to share my thoughts on the evolution of Blue teaming in this unique CTF. In many ways, this will resemble the Blue Team player’s guide I wrote about 3 years ago, but will be based on the evolution of the game and of the industry itself. That post remains relevant, and I encourage you to read it as well.


Let’s start by a refresher of the basics, as they exist today. The gameplay is a two day game, with teams being completely “blue” (defensive) on the first day, and teams moving to a “purple” stance (defending their own network, and able to attack each other as well) on the second day. During the first day, there’s a dedicated red team providing the offensive incentive to the blue teams, as well as a grey team representing the users/customers of the blue team services.

Each blue team consists of eight players and two pros. The role of the pros is increasingly mentorship and less “hands on keyboard”, fitting with the Pros v Joes mission of providing education & mentorship.


Scoring was originally based entirely on Health & Welfare checks (i.e., service up and responding) and flags that can be captured from the hosts. Originally, there were “integrity” flags (submitted by blue) and offense flags (submitted by red).

As of 2017, scoring included health & welfare (service uptime), beacons (red cell contacting the scoreboard from the server to prove that it is compromised), flags (in theory anyway), and an in-game marketplace that could have both positive and negative effects. 2018 scoring details have not yet been released, but check the 2018 rules when published.

The Environment

The environment changes every year, but it’s a highly heterogenous network with all of the typical services you would find in a corporate network. At a minimum, you’re likely to see:

  • Typical web services (CMS, etc.)
  • Mail Server
  • Client machines
  • Active Directory
  • DNS Server

The operating systems will vary, and will include older and newer OSs of both Windows and Linux varities. There has also always been a firewall under the control of each team segregating that team’s network from the rest of the network. These have been both Cisco ASA firewalls as well as pfSense firewalls.

Each player connects to the game environment using OpenVPN based on configurations and credentials provided by Dichotomy.


There has been an increasing amount of preparation involved in each of the years I have participated in PvJ. This preparation has essentially come in two core forms:

  1. Learning about the principles of hardening systems and networks.
  2. Preparing scripts, tools, and toolkits for use during the game.


It turns out that a lot of the fundamental knowledge necessary in securing a network are just basically system administration fundamentals. Understanding how the system works and how systems interact with each other provides much of the basics of information security.

On both Windows and Linux, it is useful to understand:

  • How to install & update software and operating system updates
  • How to change permissions of files
  • How to start and stop services
  • How to set up a host-based firewall
  • Basic Shell Commands
  • User administration

Understanding basic networking is also useful, including:

  • TCP vs UDP
  • Stateful vs stateless firewalls
  • Using tcpdump and Wireshark to debug and understand network traffic

Knowing some kind of scripting language as well can be very useful, especially if your team prepares some scripts in advance for common operations. Languages that I’ve found useful include:

  • Bash
  • Powershell
  • Python

Player Toolkit

Obviously, if you’re playing in a CTF, you’ll need a computer. Many of the tools you’ll want to use are either designed for Linux or are more commonly used on Linux, so almost everyone will want to have some sort of a Linux environment available. I suggest that you use whatever operating system you are most comfortable with as your “bare metal” operating system, so if that’s Windows, you’ll want to run a Linux virtual machine.

If you use a Macbook (which seems to be the most common choice at a lot of security conferences), you may want both a Windows VM and a Linux VM, as the Windows Server administration tools (should you choose to use them) only run on Windows clients. It’s also been reported that TunnelBlick is the best option for an OpenVPN Client on MacOS.

As to choice of Linux distribution, if you don’t have any personal preference, I would suggest using Kali Linux. It’s not that Kali has anything you can’t get on other distributions, but it’s well-known in the security industry, well documented, and based on Debian Linux, which makes it well-supported and a close cousin of Ubuntu Linux that many have worked with before.

There are some tools that are absolutely necessary and you should familiarize yourself with them in advance:

  • nmap for network enumeration
  • SSH for connecting to Linux Machines
  • RDP for connecting to Windows Machines
  • git, if your team will use it for managing configurations or scripts
  • OpenVPN for connecting to the game environment

Other tools you’ll probably want to get some experience with:

  • metasploit for going offensive
  • Some kind of directory enumeration tool (Dirbuster, WebBorer)
  • sqlmap for SQL injection

Useful Resources

Game Strategy

Every team has their own general strategy to the game, but there are a few things I’ve found that seem to make gameplay go more smoothly for the team:

  • During initial hardening, have one team member working on the firewall. Multiple players configuring the firewall is a recipe for lockouts or confusion.
  • Communicate, communicate, communicate. Ask questions when needed, and make sure it’s clear who’s working on what.
  • Document everything you do. You don’t need to log every command (though it’s not a bad idea), but you should be able to answer some questions about the hosts in your network:
    • What hosts exist?
    • What are the passwords for the accounts?
    • Have the passwords been changed from the defaults?
    • What services are scored?
    • What hardening steps have been applied?

Dos & Don’ts

  • DO make sure you have a wired ethernet port on your laptop, or a USB to ethernet adapter and an ethernet cable.
  • DO make sure you’ve set up OpenVPN on your host OS (not in a VM) and you’ve tested it before game day.
  • DO make sure you’ve read the rules. DON’T try to cheat, Gold team will figure it out and make you pay.
  • DO make an effort to try new things. This game is a learning experience, and you miss 100% of the shots you don’t take.
  • DO ask questions. DON’T be afraid of looking stupid – everyone in the security industry has things to learn, and the whole point of this event is that you can learn. You might even stump the pros.

Making the Most of It

Like so many things in life, the PvJ CTF is a case where you get out of it what you put into it. If you think you can learn it all by osmosis or being on the same team but without making effort, it’s unlikely to work out. PvJ gives you an enthusiastic team, mentors willing to help, and a top-notch environment to try things out that you might not have the resources for in your environment.

To all the players: Good luck, learn new things, and have fun!