Brute force jpeg's width and height

brute_force_size.py

import struct
import sys

def find_sof0_marker(data):
    for i in range(len(data) - 9):
        if data[i] == 0xFF and data[i+1] == 0xC0:
            return i
    return None

def modify_jpeg_dimensions(data, width, height):
    sof0_pos = find_sof0_marker(data)
    if sof0_pos is None:
        raise ValueError("SOF0 marker not found in the file.")

    width_pos = sof0_pos + 7
    height_pos = sof0_pos + 5

    new_data = bytearray(data)
    new_data[width_pos:width_pos + 2] = struct.pack('>H', width)
    new_data[height_pos:height_pos + 2] = struct.pack('>H', height)

    return new_data

if len(sys.argv) != 2:
    print("Usage: python script_name.py <filename>")
    sys.exit(1)

filename = sys.argv[1]

try:
    with open(filename, 'rb') as f:
        original_data = f.read()
except FileNotFoundError:
    print(f"Error: File '{filename}' not found.")
    sys.exit(1)

# Change size here
for size in range(11, 501):
    try:
        modified_data = modify_jpeg_dimensions(original_data, size, size)
        output_filename = f'flag_{size}x{size}.jpg'
        with open(output_filename, 'wb') as f:
            f.write(modified_data)

        print(f"Saved modified image with size {size}x{size} as {output_filename}")

    except Exception as e:
        print(f"Error processing size {size}x{size}: {e}")