CTF

picoCTF 2018: echooo

問題 問題文 This program prints any input you give it. Can you leak the flag? Connect with nc 2018shell.picoctf.com 3981. Source. Hints: If only the program used puts... 解答例 指針 format string attack による stack の読み込み 解説 与えら…

picoCTF 2018: SpyFi

問題 問題文 James Brahm, James Bond's less-franchised cousin, has left his secure communication with HQ running, but we couldn't find a way to steal his agent identification code. Can you? Conect with nc 2018shell2.picoctf.com 37131. Sourc…

picoCTF 2018: be-quick-or-be-dead-2

問題 問題文 As you enjoy this music even more, another executable be-quick-or-be-dead-2 shows up. Can you run this fast enough too? You can also find the executable in /problems/be-quick-or-be-dead-2_2_7e92e9cc48bad623da1c215c192bc919. Hin…

picoCTF 2018: got-2-learn-libc

問題 問題文 This program gives you the address of some system calls. Can you get a shell? You can find the program in /problems/got-2-learn-libc_3_6e9881e9ff61c814aafaf92921e88e33 on the shell server. Source. Hints try returning to systems…

picoCTF 2018: buffer overflow 2

問題 問題文 Alright, this time you'll need to control some arguments. Can you get the flag from this program? You can find it in /problems/buffer-overflow-2_4_ca1cb0da49310dd45c811348a235d257 on the shell server. Source. Hints Try using gd…

35C3 Junior CTF: 1996

問題 問題文 It's 1996 all over again! nc 35.207.132.47 22227 Difficulty estimate: very easy 問題概要 x86_64 の ELF ファイルとそのソースコードおよびそのプログラムが動いている接続先が与えられる. 解答例 指針 buffer overflow による return addr…

35C3 Junior CTF: flags

問題 問題文 Fun with flags: http://35.207.169.47 Flag is at /flag Difficulty estimate: Easy 問題概要 脆弱性のあるWebサービスの URL が与えられる. 解答例 指針 ディレクトリトラバーサル 解説 HTTP_ACCEPT_LANGUAGE の値に応じた国旗を表示するサー…

picoCTF 2018: shellcode

問題 問題文 This program executes any input you give it. Can you get a shell? You can find the program in /problems/shellcode_2_0caa0f1860741079dd0a66ccf032c5f4 on the shell server. Source. Hints Maybe try writing some shellcode? You also …

picoCTF 2018: quackme

問題 問題文 Can you deal with the Duck Web? Get us the flag from this program. You can also find the program in /problems/quackme_1_374d85dc071ada50a08b36597288bcfd. Hints: Objdump or something similar is probably a good place to start. 問…

picoCTF 2018: leak-me

問題 問題文 Can you authenticate to this service and get the flag? Connect with nc 2018shell2.picoctf.com 23685. Source. Hints: Are all the system calls being used safely? Some people can have reallllllly long names you know.. 問題概要 脆…

picoCTF 2018: buffer overflow 1

問題 問題文 Okay now you're cooking! This time can you overflow the buffer and return to the flag function in this program? You can find it in /problems/buffer-overflow-1_1_8a16ff6a1b3cfb2e42c08d9090051a5d on the shell server. Source. Hint…

OtterCTF: Gotta Go Deeper

問題 問題文 Rick and morty played with the configurations of the portal gun and accidentally got stuck in this picture. Help us get them out. GottaGoDeeper.png 問題概要 png ファイルが与えられる. 解答例 指針 binwalk + 青空白猫 解説 与えられ…

picoCTF 2018: buffer overflow 0

問題 問題文 Let's start off simple, can you overflow the right buffer in this program to get the flag? You can also find it in /problems/buffer-overflow-0_2_aab3d2a22456675a9f9c29783b256a3d on the shell server. Source. Hints How can you tr…

picoCTF 2018: in out error

問題 問題文 Can you utlize stdin, stdout, and stderr to get the flag from this program? You can also find it in /problems/in-out-error_4_c51f68457d8543c835331292b7f332d2 on the shell server Hints Maybe you can split the stdout and stderr o…

picoCTF 2017: Weird RSA

問題 問題文 We recovered some data. It was labeled as RSA, but what in the world are dq and dp Can you decrypt the ciphertext for us 問題概要 解答例 指針 中国人剰余定理 解説 与えられたファイルの中身を表示してみる. $ cat RSA.txt c: 95272795…

EKOPARTY PRE-CTF 2015: Perfect security

問題 問題文 It is not maybe so perfect. Hints: Use the golden math! crypto200.zip ※問題ファイルは下記のものを利用できる。 https://github.com/ctfs/write-ups-2015/tree/master/ekoparty-pre-ctf-2015/crypto/perfect-security 問題概要 暗号処理を…

SECCON2017 Online CTF: Ps and Qs

問題 問題文 Ps and Qs Decrypt it. update: we fixed the flag, please try to submit again. psqs1-0dd2921c9fbdb738e51639801f64164dd144d0771011a1dc3d55da6fbcb0fa02.zip (pass:seccon2017) 問題ファイルは下記のリンクのものを利用できる。 https://gi…

34C3 Junior CTF: spi

問題 問題文 I used to be a hero. Now I can't even handle this: Mitschnitt Hints: We messed up, the flag starts with 34C4 not 34C3, sorry! 問題概要 音声ファイルが与えられる。 解答例 指針 やるだけ 解説 与えられた ogg ファイルを VLC で再生速…

34C3 Junior CTF: ARM2

問題 問題文 Can you reverse engineer this code and get the flag? This code is ARM Thumb 2 code which runs on an STM32F103CBT6. You should not need such a controller to solve this challenge. There are 5 stages in total which share all the s…

34C3 Junior CTF: dotr

問題 問題文 I implemented some crypto and encrypted my secret: 03_duCbr5e_i_rY_or cou14:L4G f313_Th_etrph00 Wh03UBl_oo?n07!_e Can you get it back? 問題概要 暗号化処理をする Python3 スクリプトと暗号文が与えられる。 平文を復号せよ。 解答例 …

AlexCTF: CR3 What is this encryption?

問題 問題文 Fady assumed this time that you will be so n00b to tell what encryption he is using he send the following note to his friend in plain sight : p=0xa6055ec186de51800ddd6fcbf0192384ff42d707a55f57af4fcfb0d1dc7bd97055e8275cd4b78ec63…