QuickR

Description

Let's see if you're a QuickR soldier as you pretend to be

Solution

We are given IP:PORT to connect to:

QuickR.png

Looks like we will have to decode QR code from ASCII, specifically ANSI colors: https://gist.github.com/JBlond/2fea43a3049b38287e5e9cefc87b2124

Repeated patterns are:

\x1b[7m  
\x1b[0m
\x1b[7m  
\x1b[0m
\x1b[7m  
\x1b[0m
\x1b[41m  
\x1b[0m
\x1b[41m  
\x1b[0m
\x1b[41m  
\x1b[0m

0m is to reset color, 41m is red background, 7m wasn't found in table and it's probably black background.

from pwn import remote, info, context
import re
from PIL import Image, ImageDraw
from pyzbar.pyzbar import decode


def matrix2qr(matrix, scale=10):
    # Image dimensions
    rows = len(matrix)
    cols = len(matrix[0])
    img_size = (cols * scale, rows * scale)

    # Empty white image
    img = Image.new('RGB', img_size, 'white')
    draw = ImageDraw.Draw(img)

    for y, row in enumerate(matrix):
        for x, value in enumerate(row):
            if value == 1:  # Draw Black
                x0, y0 = x * scale, y * scale
                x1, y1 = x0 + scale, y0 + scale
                draw.rectangle([x0, y0, x1, y1], fill='black')

    return img


IP = '94.237.56.229'
PORT = 54467
ANSI_CODES = re.compile(r'\x1b\[(\d*)m')

io = remote(IP, PORT)

qr_data = []
while True:
    line = io.recvline().decode()
    if '[+]' in line:
        break

    data = []
    for color_code in ANSI_CODES.findall(line):
        if   color_code == '0':  continue       # Reset
        elif color_code == '7':  data.append(0) # Black
        elif color_code == '41': data.append(1) # Red

    if data:
        qr_data.append(data)

qr_image = matrix2qr(qr_data)
qr_text = decode(qr_image)[0].data.decode()
answer = eval(qr_text[:-2].replace('x', '*'))

info(f'{qr_text=}')
info(f'{answer=}')

io.sendline(str(answer).encode())

print(io.recvallS())

io.close()

Flag: HTB{@lriGh7_1_tH1nK_y0u``r3_QuickR_s0ldi3r}

Note: Flag middle part should have 1 tilde... formatting issue in obsidian soo...