9x9 Sudoku

9x9 Sudoku 497 Alle greier nok løse en 9x9 sudoku innen rimelig tid. Men orker du løse 50?

For å submitte korrekt brett tilbake til serveren så sender du det som en string lest tall for tall, rad for rad, fra venstre mot høyre.

Eksempel input: 823697154945231687716845239584162973291473865637958412368724591479516328152389746

ctf.uiactf.no:5006

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Denne oppgaven bør kunne løses på samme måte som jeg løste 4x4 Sudoku. Se gjerne på tidligere writeup for mer detaljer.

Vi blir møtt med følgende når vi kobler til servere:

$ nc ctf.uiactf.no 5006
Løs dette:
[2,0,4,3,0,0,1,0,7]
[0,0,0,0,1,0,0,0,8]
[0,1,0,0,0,0,0,9,3]
[0,6,8,5,7,0,0,0,0]
[1,0,2,0,0,0,7,0,0]
[0,0,0,0,4,0,0,0,0]
[8,0,1,0,0,5,6,0,2]
[7,2,0,0,0,4,9,0,5]
[5,0,0,7,0,2,0,0,4]

Vi må altså tilpasse solve.py fra 4x4 Sudoku til å fungere med 9x9 Sudoku.

Vi fortsetter å bruke https://pypi.org/project/py-sudoku/, da dette biblioteket har støtte for forskjellige brettstørrelser.

Tilpasset solve.py skript:

from array import array
from sudoku import Sudoku
from pwn import *

io = connect("ctf.uiactf.no", 5006)

# Puzzles solved so far
count = 0

# Solve 50 puzzles
while (count < 50):
    count = count + 1

    # Wait for the start of the next puzzle
    rec = io.recvuntil(b'[')
    
    # Read every line of the puzzle,
    # every line looks something like this: [0,0,4,2]
    line1 = io.recvline(False).decode()
    line2 = io.recvline(False).decode()
    line3 = io.recvline(False).decode()
    line4 = io.recvline(False).decode()
    line5 = io.recvline(False).decode()
    line6 = io.recvline(False).decode()
    line7 = io.recvline(False).decode()
    line8 = io.recvline(False).decode()
    line9 = io.recvline(False).decode()

    # Python way of parsing array strings into int arrays,
    # when the developer doesn't know Python
    b1 = [int(i) for i in line1.replace('[', '').replace(']', '').split(',')]
    b2 = [int(i) for i in line2.replace('[', '').replace(']', '').split(',')]
    b3 = [int(i) for i in line3.replace('[', '').replace(']', '').split(',')]
    b4 = [int(i) for i in line4.replace('[', '').replace(']', '').split(',')]
    b5 = [int(i) for i in line5.replace('[', '').replace(']', '').split(',')]
    b6 = [int(i) for i in line6.replace('[', '').replace(']', '').split(',')]
    b7 = [int(i) for i in line7.replace('[', '').replace(']', '').split(',')]
    b8 = [int(i) for i in line8.replace('[', '').replace(']', '').split(',')]
    b9 = [int(i) for i in line9.replace('[', '').replace(']', '').split(',')]
    b = [b1, b2, b3, b4, b5, b6, b7, b8, b9]
    print(b)

    puzzle = Sudoku(3, 3, board=b)
    print(puzzle)

    solution = str(puzzle.solve().board).replace(',', '').replace('[', '').replace(']', '').replace(' ', '')

    # Send solution
    print("Løsning: " + solution)
    io.sendline(solution.encode())

# Finished solving all 50 puzzles
print(io.recvuntil(b"Flag: ").decode())
print(io.recvline().decode())

La oss kjøre skriptet:

$ python solve.py
#...abbreviated
[[0, 5, 1, 0, 7, 0, 0, 8, 2], [0, 8, 0, 0, 0, 0, 5, 0, 0], [0, 0, 0, 8, 5, 0, 0, 0, 3], [4, 0, 6, 0, 0, 8, 0, 0, 0], [8, 2, 0, 0, 4, 3, 6, 0, 1], [0, 1, 0, 0, 0, 0, 0, 0, 0], [0, 6, 0, 2, 0, 0, 0, 4, 0], [0, 4, 0, 3, 1, 0, 8, 0, 6], [0, 0, 0, 7, 0, 0, 0, 5, 9]]

---------------------------
9x9 (3x3) SUDOKU PUZZLE
Difficulty: 0.62
---------------------------
+-------+-------+-------+
|   5 1 |   7   |   8 2 |
|   8   |       | 5     |
|       | 8 5   |     3 |
+-------+-------+-------+
| 4   6 |     8 |       |
| 8 2   |   4 3 | 6   1 |
|   1   |       |       |
+-------+-------+-------+
|   6   | 2     |   4   |
|   4   | 3 1   | 8   6 |
|       | 7     |   5 9 |
+-------+-------+-------+

        
Løsning: 351476982782931564694852713476198235829543671513627498165289347947315826238764159
Korrekt!
Flag: 
UIACTF{hekta_på_sudoku_som_om_det_var_2004}

[*] Closed connection to ctf.uiactf.no port 5006

Flagget er vårt! 🚩

Flag

UIACTF{hekta_på_sudoku_som_om_det_var_2004}