Quals NDH2K15

From Friday 3rd to Saturday 4th for 24 hours, the NDH2K15 CTF qualification rounds were hosted by HZV and Sysdream.

We would first like to apologize for the "Follow the rabbit" challenge: shortly after we started gathering writeups, we noticed a bug in the production deployment. Long story short, this challenge was not solvable and we are so sorry you guys spent time trying to make sense of it all.

However, these rounds were quite a success, mostly thanks to you. Thank you for participating such in numbers this year. We crunched some of our own numbers in return, for the love of data.

Top 10 teams

Top 10 Score Evolution


Regarding the top 10 participating countries, France was ranked first, closely followed by the USA and then the Russian Federation.

There was a total of 64 different countries, 633 signed up teams and 219 teams who scored minimum of 100 points and 880 flag captures within 24 hours.

Top 10 teams skills

We love charts! Let's see how the top 10 teams skilled in each category.

Top 10 participating countries

Country# of teams
France207 teams
United States of America(USA)44 teams
Russian Federation34 teams
japan33 teams
India31 teams
Afghanistan27 teams
South Korea21 teams
Viet Nam19 teams
Germany17 teams
Spain15 teams

First 10 validations

Here are the flags that got validated first! Game of life had quite a success. hexpresso got the "I love to be among the firsts" award.

PositionTeamDate of validationChallengeType
1hexpresso2015-04-04 00:10:18Game Of LifeCrypto
20daysober2015-04-04 00:12:19PrivateForensic
3keysec2015-04-04 00:15:19PrivateForensic
4hexpresso2015-04-04 00:15:54Clark KentCrackme/Reverse
5LSE_2015-04-04 00:17:28BpythonasticForensic
6luckyPenguins2015-04-04 00:17:54Game Of LifeCrypto
7Mr.ST4N2015-04-04 00:20:15Game Of LifeCrypto
8CandyEaters2015-04-04 00:21:27Game Of LifeCrypto
9w0pr2015-04-04 00:22:01Game Of LifeCrypto
10Drety2015-04-04 00:22:02Clark KentCrackme/Reverse

Last 10 validations

And the last validations. People played till the end! (4 seconds before the end!) Seconds really are important in CTFs. TeamTFH scores the "I am not going to stop until the end" award.

PositionTeamDate of validationChallengeType
1TeamTFH2015-04-04 23:59:56PrivateForensic
2NYUSEC2015-04-04 23:58:13BpythonasticForensic
3BH24532015-04-04 23:56:19CooperStegano
4HacknamStyle2015-04-04 23:54:10faceBoxWeb
5On est pas contents2015-04-04 23:53:59SupermanCrackme/Reverse
6On est pas contents2015-04-04 23:52:31UpdatorExploit
7MagicSmoke2015-04-04 23:52:27faceBoxWeb
80ops2015-04-04 23:50:56CooperStegano
9TeamTFH2015-04-04 23:48:46faceBoxWeb
10SpamAndHex2015-04-04 23:48:07RaptorMisc

Top 10 firstblood

First team to validate a challenge. Hexpresso got 3 first blood in the top 10! Impressive enough for the "I love blood and you are going to bleed" award.

PositionTeamDate of validationChallengeType
1hexpresso2015-04-04 00:10:18Game Of LifeCrypto
20daysober2015-04-04 00:12:19PrivateForensic
3hexpresso2015-04-04 00:15:54Clark KentCrackme/Reverse
4LSE_2015-04-04 00:17:28BpythonasticForensic
5MagicSmoke2015-04-04 00:36:20Crackme PrimeCrackme/Reverse
6khack402015-04-04 00:50:44faceSecWeb
7khack402015-04-04 01:40:43UpdatorExploit
8hexpresso2015-04-04 01:41:56CooperStegano
90x8F2015-04-04 02:06:07Mass Surveillance SoftwareCrackme/Reverse
10tasteless2015-04-04 02:14:00faceBoxWeb

Leaders in each category


Congratulations to tasteless who got 1st in 5 categories out of 7 and the well earned "I love all categories" award.

Totals per category


Categories score accumulation

Categories profitability

Which categories were the most profitable?

TypePoints / team

Top 10 sleepless teams

Who slept the less? These stats are really approximative, based on the leap between first and latest validation for each team.

1TeamTFHUptime of 23:59:57
2NYUSECUptime of 23:58:14
3BH2453Uptime of 23:56:20
4HacknamStyleUptime of 23:54:11
5On est pas contentsUptime of 23:54:00
6MagicSmokeUptime of 23:52:28
70opsUptime of 23:50:57
8SpamAndHexUptime of 23:48:08
9CandyEatersUptime of 23:47:52
10RDotUptime of 23:46:57

TeamTFH gets the "I don't sleep, sleeping is for weaklings" award.

Top 10 fastest flaggers

Who was the fastest to validate flags in average (average time to capture after the team scored its first flag)?

PositionTeamMean duration between validations# of flags
1pollypocket01:19:41(17 flags)
2hexpresso01:19:54(14 flags)
30x8F01:25:00(12 flags)
40x0000000001:31:10(10 flags)
5tasteless01:31:44(15 flags)
6CyKor01:32:41(13 flags)
7Zenk-Security01:33:37(14 flags)
8StratumAuhuur01:41:15(14 flags)
90daysober01:41:18(14 flags)
10Fapsec01:43:15(13 flags)

Congratulations to pollypocket for : "I am a speedster and I love it" award.

Top 10 slowest flaggers

Who was the slowest to validate flags in average?

PositionTeamMean duration between validations# of flags
1LSE_02:21:17(10 flags)
2binja02:18:25(10 flags)
3On est pas contents02:10:21(11 flags)
4SpamAndHex02:09:49(11 flags)
5hackgyver02:09:29(11 flags)
6dodododo02:09:19(10 flags)
7securimag02:05:34(10 flags)
8Ad Victoriam02:01:50(10 flags)
9MagicSmoke01:59:22(12 flags)
100ops01:59:14(12 flags)

Congratulations to LSE_ for the "I got time and I am going to use it" award.


All in all, this CTF was quite a success and we hope everyone had some fun. Thanks to all teams for participating to the NDH2K15 CTF quals! Most write-ups are now available on the amazing CTF writeups Githup repo, please send us your own or post a pull request directly.

We'll post write-ups for any remaining challenge in the next few days and start contacting teams next week to arrange for the prizes and the finals.

We hope to see you in June in Paris and next year for another round of qualifications.