Archenemy

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WriteUp来源

https://dunsp4rce.github.io/csictf-2020/forensics/2020/07/19/Archenemy.html

by INXS_JOY

题目描述

John likes Arch Linux. What is he hiding?

题目考点

解题思路

Its always a good practice to check the file format of all files while doing Forensics. I used the command file arched.png to check the file type. As suspected, I got this,

arched.png: JPEG image data, JFIF standard 1.01, resolution (DPI), density 300x300, segment length 16, baseline, precision 8, 1920x1080, components 3

So arched.png is a JPEG file. Let's change the extension to .jpeg

Next, I ran the image file through Stego-Toolkit and noticed that steghide found a embedded flag.zip file in the image.

Trying to unzip the flag.zip asks for a password, but we weren't provided with any passwords. So I tried to brute force the password using fcrackzip.

Fcrackzip tries all the passwords from any word-list we provide. In this case I used rockyou word-list which is a list of common passwords.

Using the command, fcrackzip -v -u -D -p /usr/share/wordlists/rockyou.txt flag.zip, we get the following output,

found file 'meme.jpg', (size cp/uc  27553/ 27752, flags 9, chk 9ed1)
PASSWORD FOUND!!!!: pw == kathmandu

So, the password for the flag.zip is kathmandu. Extracting the contents, we get a file meme.jpg. Opening it, we find the flag at the bottom of the image.

Flag

csictf{1_h0pe_y0u_don't_s33_m3_here}