GreHack

Capture the Flag

Final results

Rank	Team	Score
1	DangerousPamplemousse	3475
2	khack40	2600
3	lse	2500
4	mushd00m	1850
5	ASCCI	1300

Challenges & Write-Ups (to be completed)

Cryptography

• 150 - Say it in color: sources
• 200 - cyberTockardnautes: sources | write-up
• 250 - John & Bill: sources | write-up
• 275 - Bref mais intense: sources

Exploit

• 50 - M4st4h'Sh3ll: write-up
• 150 - Space Invaders
• 250 - Rihanna
• 400 - Game

Forensic

• 100 - user_leak: sources
• 200 - grehack.fr: sources | write-up
• 250 - hack evidence: sources
• 300 - Ultimate PNG Crypter: sources

Misc

• 100 - Rendez-vous: sources
• 200 - Things into thing: sources | write-up

Network

• 200 - The end is never the end
• 300 - bluetooth: sources
• 350 - 11112015: sources

Old

Minitel challenge making-of: here.

• 100 - Transpac GRATUIT !: sources | write-up
• 125 - Money game!: sources | write-up
• 300 - PAD NESS
• 325 - Hack the server!: sources | write-up

Reverse-Engineering

• 50 - EasyRE: sources | write-up
• 150 - reverseMe: sources | write-up
• 250 - BRUCELEE_FOF: sources
• 300 - revNNN.st: sources
• 325 - Weak Up Panda: sources | write-up
• 350 - bootme: sources
• 400 - runtime: sources
• 500 - F4b_XOR_W4kfu.exe: sources

Stegano

• 50 - NEEEEEED_TON_HEEEEEEEEEEEEEEELP: sources | write-up
• 200 - Beer: sources
• 250 - Soirée Disco !: sources
• 400 - Le retour du maître flamand: sources

Trivia

• 50 - Rumper

Web

• 50 - He's dead, Jim!
• 150 - JavaScript is everywhere!: write-up
• 300 - Days of future past: write-up
• 400 - Put your own music

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Global information

• GreHack 2015 CTF starts at 9:00pm and ends at 6:00am.
• It is Jeopardy style by teams.
• There will be prizes to win (see corresponding section)
• Registration is required. An entrance ticket for the conferences gives access to CTF. CTF-only tickets will also be available.
• We will provide food, drinks and music.
• Challenges are written by Securimag.

Categories

Challenges will treat the following topics (non-exhaustive):

• Cryptography
• Reverse-Engineering
• Exploit
• Web
• Forensic

Hardware requirements

Individual hardware requirements: please come with

• a computer,
• a RJ-45 cable to access challenges,
• a brain.

Team hardware requirements: each team needs to bring:

• a L2 switch,
• Power strip(s).

Prizes

Non-exhaustive list of prizes for the best teams (to be completed):

• Chartreuse bottles and sweat-shirts
• OFC lock-picking kits
• Misc subscriptions

Basic rules

• Competitors have to be physically present.
• Maximum number of participants per team is 8.
• Internet connection will (probably) be provided.

It is strictly prohibited and can be subject to disqualification to:

• attack machines other than designated ones,
• share flags or solutions between teams,
• DDos GreHack CTF infrastructure.

Training

You can prepare yourself by giving a look to previous grehack challenges:

• 2013
• 2012