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ASIS CTF 2020 Quals - Pwn Writeup

I wrote the 6 pwn tasks of ASIS CTF 2020 Quals. Here is the brief overview of them. Challenge Vulnerability Estimated Difficulty Full Protection stack overflow, fsb warmup babynote integer overflow (to get out-of-bound address write) easy …

Defenit CTF 2020 Writeups

We zer0pts played Defenit CTF 2020 and reached 4th place! It was a really amazing CTF! Other members' writeups: furutsuki.hatenablog.com st98.github.io Here is the tasks and solvers for some challenges I solved. bitbucket.org [Pwn 656pts] …

Pwn2Win CTF 2020 Writeups

Pwn2Win CTF 2020 had been held from May 30th for 48 hours. I played it in zer0pts and reached 6th place. Especially pwn tasks were a lot of fun! [Pwn 263pts] At Your Command [Pwn 298pts] Tukro [Pwn 340pts] Trusted Node [Web 171pts] A Paylo…

SECCON Beginners CTF 2020 作問者Writeup

はじめに 5月23日14:00から24時間、初心者向けのSECCON Beginners CTF 2020を開催しました。 といっても全問が初心者向けな訳ではなく、中級者でも難しいと感じるような問題もちらほらあったと思います。 また、CTFを本当に初めて触るという方にとってはBegi…

SpamAndFlags 2020 Writeups

I played "S㎩mAndFlags Uけimate w呎は屸de C㏊mᒆonship Teaser - ㎩㏚i㎄ Edition" in shibadogs. We reached 6th place :yay: Thank you @SpamAndHex for hosting the CTF! [rev+misc] TAS (1-5) [pwn] Nativity Scene [pwn] Secstore #2 The tasks and …

IJCTF 2020 Writeups

I played IJCTF 2020 in zer0pts and we got 3rd place. Other member's writeup: st98.github.io [pwn 100pts] Input Checker [pwn 620pts] Babyheap [rev 728pts] Rev 0 [rev 986pts] Rev 2 [forensics 998pts] List Of File Type [rev+web+pwn 1000pts] b…

PlaidCTF 2020 Writeups

I played PlaidCTF in shibad0gs and reached 38th place. I'm going to write up the challenges I solved during the CTF. I don't write about "YOU wa SHOCKWAVE" as I mostly guessed the flag. (It was about disassembling shockwave media --> findi…

HexionCTF 2020 Writeups

I played HexionCTF in zer0pts and we got 1st place. The tasks are decent-level, fun and well-designed. Thank you @hexion_team for the nice CTF! Other member's writeup: st98.github.io [Pwn 940pts] WWW [Pwn 988pts] Hangman [Pwn 998pts] Text …

House of Husk

CTF

About Yesterday I came up with an idea of a new heap exploitation technique. As far as I googled it, nobody had published the technique yet and I named it "House of Husk." The technique makes it easy to control RIP under the condition that…

House of Husk (仮)

CTF

はじめに ヒープ大嫌いなのですが、多分まだ誰も公開していないヒープ系exploit手法を思いついたので書きます。 調べても出てこなかったので既出じゃないと信じて「House of Husk」と名前を付けました。 これ系に命名規則があるのか不明だし名前も思いつかな…

FireShell CTF 2020 Writeups

FireShell CTF had been held from March 22th JST for 24 hours. I played this CTF in zer0pts and we reached 3rd place. I solved only two pwn tasks and one easy crypto/rev, but the pwn tasks are tough and I'm going to write the solutions for …

SuSeC CTF 2020 Pwn Writeups

SuSeC CTF 2020 had been held from 15th March 06:30 UTC for 36 hours. I wrote 3 pwn tasks for this CTF. (I don't know of any other tasks.) The tasks and solvers are available here: bitbucket.org I hope you enjoyed my pwn challenges :) [182p…

CONFidence CTF 2020 Teaser Writeups

I played CONFidence CTF 2020 in zer0pts. We got 786pts in total and reached 19th place. It was pretty hard but a fun CTF. Other members' writeups: st98.github.io Files and solvers for some challenges: bitbucket.org [misc 37pts] Hidden Flag…

Kernel Exploitで嵌ったときのチェックリスト

CTF

はじめに Kernel Exploitを初めて1ヶ月半くらいが経ちましたが、カーネルランドはデバッグが大変なので「なぜかexploitが動かない」ってなったときのチェックリストを作りました。 僕は大量に時間を溶かしたのですが、皆はこんな人間にならないでね。 ユーザ…

zer0pts CTF 2020 開催記

CTF

はじめに 2020年03月07日00:00から09日00:00 UTCにzer0pts CTF 2020を開催しました。 今回はいままでと違い、zer0ptsで開催したという点と、CTFtimeに載せたという点で初だったので緊張感がありました。 開催記を残すとともに、CTFtimeに載せる手順や攻撃へ…

Codegate CTF 2020 Preliminary Writeup

I played Codegate CTF 2020 in shibad0gs. I was busy for another upcoming event and couldn't work on it full time but I solved some challenges and we reached 30th place. As the challenge doesn't have category, I randomly picked up tasks. [3…

HackTM CTF Quals 2020 Writeup

HackTM CTF was held from February 1st to 3rd for 48 hours. I played it in zer0pts and we reached to 8th place. Thank you @WreckTheLine for hosting the CTF! The tasks and solvers for some challenges I solved are available here: bitbucket.or…

NITAC miniCTF 3rd 作問writeup

こんなCTFがあったんで参加しようと思ったのですが、こんなツイートを見て作問お手伝いすることにしました。 作問に参加した時点では割と自明問が多く、某氏とか某氏に即全完されそうな感じだったので、私は若干難しめのものを作りました。 といっても初心者…

Insomni'hack teaser 2020 Writeup

I played Insomni'hack teaser 2020 in shibad0gs. There're only 1 misc, 1 rev, 1 forensics, 3 crypto and 4 web. We solved 4 tasks in the first 4 hours and that's it lol. As the web tasks are too guessy, I just solved the misc, forensics and …

Gomium BrowserのWriteup【Google CTF 2019 Finals】

はじめに 今日サイバーセキュリティ系LT会というのに参加したのですが、そこでhamaさんが発表されていたgoの処理系がunsafeな話が面白かったので、解説されていた問題を解こうと思います。 内容はgoには標準でdata raceが存在し、任意のgoコードが実行出来る…

Contrail CTF 2019のWriteup

Contrail CTFが12月30日から1月4日まで開催され、zer0ptsで参加しました。 全体で4786点を獲得して1位でした。 解いた問題のwriteupを簡単に書きます。 [pwn 100pts] welcomechain [pwn 304pts] instant_httpserver [pwn 356pts] babyheap [pwn 100pts] poke…

BambooFox CTF 2019-2020 Writeup

BambooFox CTF had been held from December 31th to January 1st. I played it a bit in zer0pts and we stood 5th place. All of the pwn-related tasks were very fun! Thank you for hosting the CTF and happy new year :) [Pwn 323pts] note [Pwn 357p…

Christmas CTF 2019 Writeup

XMAS CTF was held in Christmas for those who are lone! We zer0pts played this CTF and I worked on pwn tasks which are well-designed. I couldn't work on it full-time because I had school but still enjoyed the CTF :) [rev 919pts] welcome rev…

2019年のpwn問を全部解くチャレンジ【後半戦】

この記事はCTF Advent Calendar 2019の23日目の記事です。 はじめに この記事は「2019年のpwn問を全部解くチャレンジ【前半戦】」の続きで、解く対象の問題も前の記事と基本同じです。 が、ちょっと条件を追加します。 javascriptや独自vm、コンパイラ、イン…

SECCON CTF 2019 FinalのWriteup

2019年もSECCONが秋葉原で開催されました。 今回はNaruseJunで国際決勝に参加し、最終的には4323点を獲得して1位でした。 SECCONについて 国内チームも参加しやすい敷居の低い競技を毎年開催していただき感謝です。 ただ年々セキュリティコンテストからプロ…

watevrCTF 2019 Writeup

I played watevrCTF, a Swedish CTF held from December 13th to 15th, in zer0pts. We got 4869pts and stood 3rd place. Most of tasks are well-designed and I really enjoyed the CTF. Thank you to watevr for hosting the CTF! [pwn 33pts] Voting Ma…

CTFZone 2019 Quals Writeup

I played CTFZone 2019 Quals in zer0pts. Our team got 879pts and kept 37th place. Thank you for organizing the CTF. Here's the tasks and solvers for some challenges I solved. https://bitbucket.org/ptr-yudai/writeups/src/master/2019/CTFZone_…

TSG LIVE! CTF 4のwriteup

なんかtwitterで流れてたのでzer0ptsで参加しました。 75分という短時間で早解きが要求されるCTFです。 TSGの問題は良問が多いので好きです。75分なので問題数は少なかったですが、チームメンバーの様子を見ていても面白い問題が多かったようです。 私はpwn…

Newbie CTF 2019 Writeup

I played Newbie CTF which was held from November 2nd to 3rd in zer0pts. The CTF had some problems in their challenges, servers, and so on but I enjoyed it. We got 15849pts and reached 1st place. Here I'm going to write the solutions for pw…

hack.lu CTF 2019 Writeup

I played hack.lu CTF 2019 in zer0pts. Although I couldn't play it full-time as it was in weekdays, I managed to solve some challenges after school. We got 1709 points and reached 27th place. It was a fun CTF and I enjoyed it. Thank you for…