Writeup by yvan00877 for Embroidery

Get data

• Download the embroidery-usbdisk.img.xz file
• Decompress it
• Mount the disk image embroidery-usbdisk.img
• The image contains only one file : fcsc.exp
• Copy this file to a work directory

Search for info on this file format

• A quick Google search shows that this file format is used by embroidery machines.
• Further research shows a Python library capable of reading, writing, and converting this format.

Read the flag

• It’s time to write a little Python code

from pyembroidery import read, EmbPattern, write_png

input_file = "./fcsc.exp"
output_file = "./fcsc.png"

pattern = read(input_file)
write_png(pattern, output_file)

• Run the code
• The resulting file contains the embroidered flag pattern