CTF-BR! – p7 – reader (Day 7)

p7 – reader (Day 7)

Posted 9 de julho de 2015

> ADCTF > ADCTF 2014 > p7 - reader (Day 7)

Read 10 times.
nc adctf2014.katsudon.org 43010

O objetivo nesse desafio era conectar no servidor e decodar 10 códigos de barra que apareciam em ASCII mode. A imagem no fim do post ilustra bem como eram.

Solução

barcode.py:

#! /bin/python

import socket

code_03 = {'100010100':'0','101001000':'1','101000100':'2','101000010':'3','100101000':'4','100100100':'5','100100010':'6','101010000':'7','100010010':'8','100001010':'9','110101000':'A','110100100':'B','110100010':'C','110010100':'D','110010010':'E','110001010':'F','101101000':'G','101100100':'H','101100010':'I','100110100':'J','100011010':'K','101011000':'L','101001100':'M','101000110':'N','100101100':'O','100010110':'P','110110100':'Q','110110010':'R','110101100':'S','110100110':'T','110010110':'U','110011010':'V','101101100':'W','101100110':'X','100110110':'Y','100111010':'Z', '101011110':'', '100101110':'-', '111010100':'.', '111010010':' ', '111001010':'$','101101110':'/','101110110':'+','110101110':'%','100100110':'$','111011010':'%','111010110':'/','100110010':'+'}

HOST = "adctf2014.katsudon.org"
PORT = 43010

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((HOST, PORT))

while 1:
    data = s.recv(256) + s.recv(256)

    print data

    if '\xe2\x96\x8c' not in data:
break

    char_codes = []
    text = ''

    data = data.replace(' ', ' ')

    for i in range(0, len(data)-3, 3):
        temp = data[i] + '' + '' + data[i+1] + '' + data[i+2]
        if temp == '\xe2\x96\x8c':
text += '10'
        elif temp == '\xe2\x96\x88':
text += '11'
        elif temp == '\xe2\x96\x90':
text += '01'
        elif temp == ' ':
text += '0'
        else:
            print "Error: ", temp

    print text

    out = ""

    for i in range(0, len(text)-9, 9):
        out += code_03[text[i:i+9]]

    print out[:-2]

    s.send(out[:-2])

#! /bin/python

import socket

code_03 = {'100010100':'0','101001000':'1','101000100':'2','101000010':'3','100101000':'4','100100100':'5','100100010':'6','101010000':'7','100010010':'8','100001010':'9','110101000':'A','110100100':'B','110100010':'C','110010100':'D','110010010':'E','110001010':'F','101101000':'G','101100100':'H','101100010':'I','100110100':'J','100011010':'K','101011000':'L','101001100':'M','101000110':'N','100101100':'O','100010110':'P','110110100':'Q','110110010':'R','110101100':'S','110100110':'T','110010110':'U','110011010':'V','101101100':'W','101100110':'X','100110110':'Y','100111010':'Z', '101011110':'', '100101110':'-', '111010100':'.', '111010010':' ', '111001010':'$','101101110':'/','101110110':'+','110101110':'%','100100110':'$','111011010':'%','111010110':'/','100110010':'+'}

HOST = "adctf2014.katsudon.org"

PORT = 43010

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

s.connect((HOST, PORT))

while 1:

data = s.recv(256) + s.recv(256)

print data

if '\xe2\x96\x8c' not in data:

break

char_codes = []

text = ''

data = data.replace(' ', ' ')

for i in range(0, len(data)-3, 3):

temp = data[i] + '' + '' + data[i+1] + '' + data[i+2]

if temp == '\xe2\x96\x8c':

text += '10'

elif temp == '\xe2\x96\x88':

text += '11'

elif temp == '\xe2\x96\x90':

text += '01'

elif temp == ' ':

text += '0'

else:

print "Error: ", temp

print text

out = ""

for i in range(0, len(text)-9, 9):

out += code_03[text[i:i+9]]

print out[:-2]

s.send(out[:-2])

Clique na imagem para ampliar:

Flag:

The flag is ADCTF_4R3_y0U_B4rC0d3_R34D3r.

Criador por

Epic Leet Team

Álisson Bertochi