UMassCTF'21: Scan Me

Scan Me

Category: misc

128 points

The top layer is a lie.

http://static.ctf.umasscybersec.org/misc/8e0111c9-d8d0-4518-973d-dbdcbd9d5a42/scan_me.xcf

Created by Seltzerz#6678

Solution

file scan_me.xcf 

scan_me.xcf: GIMP XCF image data, version 0, 800 x 600, RGB Color

Under visible layer there’s one with the actual challenge.

It contains the broken QR code and the challenge is about fixing it.

First of all I didn’t have enough knowledge about QR codes, so I started research. Finally, I’ve found QR Code Tutorial which gave me all the information needed to start my work.

I’ve done some pixel art by redrawing the whole QR code pixel by pixel. I’ve also added missing finder pattern, dark module and timing pattern. The result below.

After scanning…

Under the given address there’s an image with the flag.

Flag

UMASS{QR-3Z-m0d3}