PROBLEM
You walk past the bin, You do the sin. Bin is not the way, Walk it by the way.
Here is a Image, Now give me the flag. stromwalk.jpg
SOLUTION
Notice those bin and walk in the question well it refers to binwalk.
So simply run binwalk on the given image and we see:
➜ binwalk stromwalk.jpg
DECIMAL HEXADECIMAL DESCRIPTION
--------------------------------------------------------------------------------
0 0x0 JPEG image data, JFIF standard 1.02
30 0x1E TIFF image data, little-endian offset of first image directory: 8
451 0x1C3 Unix path: /www.w3.org/1999/02/22-rdf-syntax-ns#">
899 0x383 Unix path: /purl.org/dc/elements/1.1/">
1327 0x52F Unix path: /ns.adobe.com/xap/1.0/mm/">
29457 0x7311 Zip archive data, at least v2.0 to extract, compressed size: 3088, uncompressed size: 3129, name: qrcode.png
32693 0x7FB5 End of Zip archive
Well there's a hidden ZIP and an image file there. So just extract them using binwalk
>>> binwalk -e stromwalk.jpg
DECIMAL HEXADECIMAL DESCRIPTION
--------------------------------------------------------------------------------
0 0x0 JPEG image data, JFIF standard 1.02
30 0x1E TIFF image data, little-endian offset of first image directory: 8
451 0x1C3 Unix path: /www.w3.org/1999/02/22-rdf-syntax-ns#">
899 0x383 Unix path: /purl.org/dc/elements/1.1/">
1327 0x52F Unix path: /ns.adobe.com/xap/1.0/mm/">
29457 0x7311 Zip archive data, at least v2.0 to extract, compressed size: 3088, uncompressed size: 3129, name: qrcode.png
32693 0x7FB5 End of Zip archive
You'll have a folder with random name. In that folder we have an image called qrcode.png and I don't need to tell you this that it's an image of a qrcode 😄.
Now go to this website give your qrcode image to it and you'll get back a link to a paste and there you'll get
--[------->++<]>-.[->+++<]>.+++++.-----------.+++++++++.+++++++++.+[->+++<]>++.+.-[----->+++<]>.--[->++<]>-.+.++[->+++<]>++.+++++.++++++.[->+++++<]>+++.+[--->+<]>+++.++[->+++<]>.>++++++++++.--[----->+<]>+.+++++.++++++.[---->+<]>+++.+[----->+<]>.------------.++++++++.+++++.++[++>---<]>.+.>++++++++++.>--[-->+++++<]>.>++++++++++.[->+++<]>++....[-->+++++++<]>.+++++.-.-.-[--->+<]>++.------.+[->++<]>+.+++++.+++++++++.--------------.>--[-->+++++<]>.-[->+++++<]>.[--->+<]>----.[-->+<]>-----.---.-[----->+<]>--.--------.-[--->+<]>--.+[->+++<]>+.++++++++.------------.+[-->+<]>+.++++.-----[->++<]>-.-[->++++++<]>.--[->++<]>-.+[-->+<]>+++++.+++[->++<]>+.+++[++>---<]>.++[->++<]>..-[--->+<]>.[->+++++<]>++.++++.-[-->+<]>-..++++++[->++<]>.[----->+<]>+.-[---->+<]>+++.+++++++.-[-->+++<]>-.>++++++++++..[->+++<]>++....---[----->++<]>.-------------.[--->+<]>---.+.---.----.-[->+++++<]>-.[-->+++<]>.+++++++++++.>++++++++++.>--[-->+++<]>.
Yes that's brainfuck don't even thing and just go to this put the given code and you'll have:
$bfi main.bf
#include<stdio.h>
int main()
{
puts("GLUG{br41nfuck_15_4c7u4lly_c00l}");
return 0;
}
FLAG - GLUG{br41nfuck_15_4c7u4lly_c00l}