Encryptctf Journeytothecentreofthefile2

Challenge: Journey to the centre of the file 2(for 150 points, static) [Forensics]

Challenge description:

This challenge unlocks after completing "Journey to the centre of the file 1" challenge.

[Improvise. Adapt. Overcome](https://imgur.com/gallery/wMbXB)
file: (ziptunnel2)[ ]
Author: maskofmydisguise

Let’s capture tis fl4g:

We are given a ziptunnel2 file here. This is level 2 of (Journey to the centre of the file 1)[ ] Challenge. Here, instead of just gzip we have various types of compression at random stages! But, as the challenge description says we gotta Improvise. Adapt. Overcome So let’s make some changes to our get_flag.sh script.

#!/bin/bash

mkdir tmp/
cp ziptunnel2 tmp/ # creating tmp directory and solving there coz we use `ls` to get filenames
cd tmp/
filename=$(ls)
rm -r tmp2/
mkdir tmp2/
cp $filename tmp2/
cd tmp2/
filename=$(ls)
while [ 1 ]
do
	file $filename
	file $filename | grep "bzip2"
	if [ "$?" -eq 0 ]
	then
		mv $filename $filename.bz2
		bunzip2 $filename.bz2 > /dev/null
		filename=$(ls)	
	fi

	file $filename | grep "Zip"
	if [ "$?" -eq 0 ]
	then
		mv $filename $filename.zip
		unzip $filename.zip > /dev/null
		rm $filename.zip > /dev/null 2>&1
		filename=$(ls)	
	fi

	file $filename | grep "gzip"
	if [ "$?" -eq 0 ]
	then
		mv $filename $filename.gz
		gunzip $filename.gz > /dev/null
		filename=$(ls)
	fi

	file $filename | grep "ASCII"
	if [ "$?" -eq 0 ]
	then
		echo 
		echo
		echo "Flag Found!"
		echo
		cat $filename
		echo
		echo
		break
	fi
done

This script directly spits out the flag,

FLAG: encryptCTF{f33ls_g00d_d0nt_it?}

Now, one thing is that I am not gonna explicitly explain every line of the code, cz John Hammond actually has done a writeup video on a similar challenge.

YeAh, I know what you thinkin’ it was copied. OMG!

Thankyou for reading, happy hackin’! ~ eshaan7