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BambooFox CTF 2019 Oracle writeup

We're given the server.py and the nc information. #!/usr/bin/env python3 from Crypto.Util.number import * with open("flag", "rb") as f: flag = int.from_bytes(f.read(), "big") def genkeys(): e = 65537 while True: p, q = getPrime(512), getPr…

UTC-CTF writeup

I played UTC-CTF as wr0ngf1ag alone. Luckily, I reached 7th place at the end of that great competition! There were many well-designed challenges and educational challenges. Thanks to all the admins! [pwn] Simble bof (baby) [pwn] RIP my bof…

watevrCTF writeup

I played wateverCTF as a member of zer0pts. Luckily, my teammates are awesome. We reached 3rd place at the end of the competition! The scoreboard is pretty cool. And the infrastructure is so good. Moreover, there are very cool challenges. …

CTFZone 2019 Quals Writeup

[Crypto] Agents AES-OFB encrypted json which may formed : {"trusted": 0, "N": ..., "e": 65537} (@ptr-yudai guessed this) when we turned trused into 1, the server returned RSA-encrypted secrets using N and e in json. Since encryption mode w…

Square CTF 2019 Writeup

I played Square CTF 2019. I enjoyed some challenges. Thanks for the admins to hold it. However, scoring system should be improved. Writing up I solved. [100] Talk to me [Web 600] Lockbox [100] Talk to me There was a ruby interpreter which …

picoctf2019 writeup

チーム zer0pts として picoctf2019 に参加していました。チームとしては shark on wire 2 Time's Up, Again! zero_to_hero が解けず 30751点で58位でした。私はCryptographyやReverse Engineeringを中心に解きました。面白かった問題についてwriteupを書き…

InCTF Writeup

I played InCTF as a member of zer0pts. We reached 22nd place and got 2302 points. It was a very good CTF. Thanks all the admins for holding such a great competition! I solved PHP+1.5 and PHP+2.5 during the competition. Write it up. [Web 74…

はてなサマーインターン2019 に参加していました

退屈と言える程 幸せじゃないけれど 不幸だと嘆く程 暇もない毎日 ――普通の人々 専攻科1年ということもあり、そろそろこの先の人生をどう振るのか考えなければならない時期なので、業界や会社を見学する気持ちで、はてなサマーインターン2019に参加してきま…

InterKosenCTF2019 開催記

初級〜中級者向けのCTF、 InterKosenCTFを開催したので色々まとめておきます。 感想 CTF開催するのしんどいけど楽しいです。スコアサーバが50Xを返したときは最悪ですが。 概要 チームinsecure( @theoldmoon0602 , @ptr-yudai, @yoshiking)として、 2019-08…

ISITDTU CTF 2019 Quals Writeup

I played the ISITDTU CTF 2019 Quals as a member of zer0pts. We got 7655 points and reached 10th place. Excepting that the score server was very slow entire the competition and some of challenges were not CTF challenges, I almost enjoyed th…

HSCTF 6 writeup

HSCTF 6 had been held from June 3, 2019 7:00 AM EST — June 7, 2019 7:00 PM EDT. We played this competition as a team yoshikingdom. It is a joke team because we only participated in the last 19 hours. We got 12761 points and reached 11th pl…

Facebook CTF writeup

I played Facebook CTF as a member of team zer0pts. We were in 18th place and got 9372 points. There were a lot of well-crafted challenges. I enjoyed all the challenges I tried even though I couldn't solve some of them. [Crypto 453points (7…

SECCON Beginners CTF 2019 writeup

チームzer0ptsでSECCON Beginnners CTF 2019に参加し、5477点を獲得して1位でした。初心者としては上の方にいることが確認できてよかったと思います。チームメイトが優秀だったので、私は易しい問題ばかり解いていました。 [Crypto 115pts(192 solves)] [war…

RCTF 2019 writeup

RCTF 2019 has been held. We participated in it as team zer0pts and were the 59th place with 791 points. I'm writing up about the baby crypto challenge. [Crypto 400pts(Solved by 31 teams)] baby crypto nc 45.76.208.70 20000 nc 207.148.68.109…

TSG CTF 2019 Writeup

insecureとしてTSG CTFに出ていました。868点で18位でした。難しくて実力不足を感じました。泣いた。 [Forensics 92 + 178 pts (90 + 61)Solves] Obliterated File & Obliterated File Again [Crypto 497pts (10 Solves)] OPQRX [Forensics 92 + 178 pts (90…

ångstromCTF 2019 writeup

I played ångstromCTF 2019 as a member of zer0pts. We gained 3730pts totally and got 8th place. I learned so many things from all the challenges. Thanks to all the admins! [Rev 130pts] Icthyo [Crypto 100pts] Paint [Crypto 120pts]Secret Shee…

ASIS CTF Quals 2019 Writeup

I played ASIS CTF Quals 2019 as a member of insecure. We got 224 pts and reached 88th place. Thanks to all the admins for the great competition. [Coding 67pts(78 Solves)] Flag collision [Crypto 44pts(135 Solves)] A delicious soup I wanted …

CPCTF2019 writeup

CPCTF 2019に参加していました。最終的に8100点で3位でした。嬉しいです。全ての問題のwriteupを書くのは大変なので、面白かった問題や回答数の少ない問題についてのwriteupをします。 [Crypto 300]worm_eaten [Crypto 300]SHAII_we_collide? [Binary 300]fa…

PlaidCTF 2019 writeup

I played PlaidCTF 2019 as a member of insecure. Our team got 261pts and reached the 116th place. I don't feel it's a good result. All the challenges I tried were very difficult but also a lot of fun. [Misc 10pts(368 solves)] docker [Misc 1…

Sunshine CTF 2019 writeup

I attended Sunshine CTF 2019 as a member of zer0pts. We came in the 10th place with 3255 points at the end of the CTF. I regret that I gave up to solve challenges during the competition. I solved only two scripting challenges. I'm going to…

Securinets Prequals 2K19 writeup

We made a new team zer0pts and attended Securinets Prequals 2K19. We got 23393 points and reached 2nd place!! Thanks to all the admins for this great CTF! I solved some of the challenges and I'm going to write up them. [Misc 200pts (321 so…

UTCTF Quals 2019 Writeup

I participated in the UTCTF Quals 2019 as a member of a team insecure. We reached 18th place with 8250points. Many interesting challenges were provided in the competition. Thanks to all the admins! I'm writing up some challenges which I so…

AeroCTF Quals 2019 Writeup

I participated in an AeroCTF Qual 2019 as a member of team insecure. We reached 14th place with 3411pts. Thanks to admins for a great competition. I solved the following challenges. I'm going to describe them. [Warmup 100pts(23 solves)]mis…

TAMUCTF 2019 Writeup

TAMU CTF had been held from 2019/2/23 09:00 to 2019/3/4 09:00(JST). Our team insecure (me, ptr-yudai and yoshiking) participated in the competition. We got 19162pts and reached 16th position. There were many valuable challenges in the CTF,…

t-cache poisoning: FireShell CTF 2019 babyheap

今日はptr-yudaiにt-cache poisoningというテクニックを教えてもらいました。これを使って解ける問題も解き方も教えてもらったので、忘れないうちに書いておきます。 t-cache t-cacheは2017-08-02にリリースされたglibc 2.26から追加されています(t-cacheが…

FireshellCTF writeup

I participated in Fireshell CTF as a member of team insecure with ptr-yudai, yoshiking, thrust2799. We got 16th place at the end of the CTF. I solved some challenges: babycryptoweb, biggars, and Blackbox-0. Thanks, admins for this great CT…

InterKosenCTF writeup

公式writeupというほど大仰なものではないです。どちらかといえば作問振り返りで、自分語りに該当するやつなので、ちゃんとしたwriteupは参加者の皆さんのものを探してください。見つけ次第このエントリでもリンクを貼りたいとは思っています。 あとここにwr…

InterKosenCTFを開催した

あわせてよみたい: furutsuki.hatenablog.com ptr-yudai.hatenablog.com InterKosenCTF反省会 我々insecure(ptr-yudai, theoldmoon0602, thrust2799, yoshiking)は、2019-01-18 21:00 ~ 2019-01-20 21:00 (JST)の48時間、高専生向けと銘打ったCTF、InterKos…

SECCON国内大会 参加記

毎度のことながらSECCONは解けなさすぎてwriteupではなくて参加記になります。 今年もまたSECCON国内大会にinsecureという命名センスが飛んでいったチームで参加しました。今年もまた連携大会を通しての出場で、KOSENセキュリティコンテストでの優勝によるも…

TenDollarCTF 2018 writeup

2018/11/24 9:00〜2018/11/25 15:00の期間にTenDollar CTF(tendollar.kr)に参加していました。このCTFは個人戦&招待制という色の強いCTFです。なんでこうしてるんだろう。ともかく、st98プロにinvitation codeをもらってzer0ptsとして参加しました。 点数が…