Join Us August 1st–4th, 2013

All 4 days just $180 USD!

at the Rio Hotel in Las Vegas!

Cash only at the door.

Capture the Flag at DEF CON 21

Welcome Legitmate Business Syndicate as the new DEF CON CTF Organizers!



Exciting news: we've decided on a schedule for the 2013 DEF CON CTF season! Join us this year as we host qualifications the weekend of June 15-17. Registration will open on May 1.

Changes for 2013

We have a new and exciting team size limitation for you! Should you qualify, your team in Vegas will be limited to eight: you won't be allowed more than eight seats at your table. Work with us on this :) If you've got friends dropping by with food/booze, that's cool. If you've got runners carrying flash drives back and forth between the competition area and the rest of the team holed up in hotel rooms, that's not. We're building fewer and harder challenges for the competition: parallelization will be of limited value, and a win with a small team is more elite anyways.

Web stuff won't just be simple baby's first SQLi this time. It'll be hard, it'll be related to real-world stuff, and we think you'll enjoy it.

We're dropping categories from previous years. You can leave your forensics tools at work, you're not going to be undeleting .TGA files from FAT12 dumps this year. You don't need to bookmark all those DEF CON history pages either, trivia is gone, and we promise to not make you answer "____ ___ ______!"

Not changed for 2013

Do go brush up on your assembly, and don't just stop at Intel/AMD's offerings. ARM processors are scary popular, PPC still exists lol, and who knows what other popular architectures might make a cameo. Expect to be taking over applications remotely, reverse engineering some ridiculous binaries, and writing mind bending shellcode.

More open and less ambiguous

We have a presence on the official DEF CON forums now. We won't monitor it 24/7, but as quals draws closer, we hope to answer some questions.

Additionally, you can follow @legitbs_ctf on Twitter; some of the individual businessmen have Twitter accounts too, and may (or may not) have relevant information.

Latest Tweet

Follow @legitbs on Twitter!

DEF CON 21 CTF Schedule

Check out for all the details!

April 1
Schedule Announced

May 1
Registration Open

June 15, Midnight UTC
Qualification Starts

June 17, Midnight UTC
Qualification Ends

August 2
Competition Starts

August 4
Competition Ends

Quals start times by Time Zone
TZ Quals Start Quals End
Tokyo June 15, 9am June 17, 9am
Moscow June 15, 4am June 17, 4am
UTC June 15, Midnight June 17, Midnight
New York June 14, 8pm June 16, 8pm
LA June 14, 5pm June 16, 5pm

CTF Resources

Check out the DEF CON CTF Archive page for write-ups and more!


A brief history of the Capture the Flag contest by DDTek's vulc@n.


Legitimate Business Syndicate: 2013
DDTek: 2009 - 2012
Kenshoto: 2005 - 2008
Ghetto Hackers: 2002 - 2004


Caezar's (Ghetto Hackers) presentation from Black Hat Japan on CTF Games: Slides | Audio

CTF Explained - Youtube Video:

Archive of 2006 to 2009 DEF CON CTF and CTF Quals:

Getting the Most Out of Capture the Flag at DEF CON 17: 17 Hacking Conference Presentation By Psifertx - Maximum CTF Getting the most out of Capture the Flag - Video and Slides.m4v