CTF题目 June. 22nd 2021

Chalkboard

Solve the equations embedded in the jpeg to find the flag.

https://ctflearn.com/challenge/download/972

Flag format: CTFlearn{**************}

链接下载一张图片：

图片的EXIF信息中有flag，可以用图虫查看。

Time Traveller

Let’s take a trip to nasa.gov on December 31, 1996. If you can tell me what email NASA listed on their website, I’ll provide you with 10 points.

Format: CTFlearn{email}

使用Web Archive查看网页的历史存档。

可以找到1996年12月31日nasa.gov的存档：NASA Home Page/Mars Pathfinder Sites (archive.org)

Gobustme 👻

Some ghosts made this site 👻, it’s a little spooky but there’s a bunch of stuff hidden around.

gobustme.ctflearn.com

Flag format: CTFlearn{************}

点开这个网址，视频下方第一个链接，指向一个gobuster的教程。

在Kali里面用gobuster扫一遍网站，可以发现flag：https://gobustme.ctflearn.com/hide/

1

gobuster dir -e -u https://gobustme.ctflearn.com/ -w /usr/share/wordlists/dirb/common.txt

Raspberry

Raspberry Reversing Challenge

This 20 point challenge is specifically created for people new to reversing and assembly language programming. You can solve this first using Ghidra or IDA if you want to just get the flag and solve the challenge.

If you want to start learning some assembly language programming to build the skills needed to solve some of the more difficult reversing challenges, then step through the debugger and examine the registers to see how each each letter in the flag is determined to be correct or incorrect.

This challenge gives people new to assembly language programming the chance to learn mov, xor, cmp, jmp, call, add, sub, mul, div and shl instructions when they operate on a single byte (for most of the letters in the flag).

Good luck and have fun!

https://ctflearn.com/challenge/download/1080

Flag format: CTFlearn{*******}

下载下来一个zip：Raspberry.zip

解压后有个Raspberry程序，可以用./Raspberry CTFlearn{*********}测试flag的正确性。

查看他的汇编代码，算出flag。

第15个字符的计算过程比其他的复杂，可以通过IDA看反汇编代码。