Python Challenge - Level 20

Problem

but inspecting it carefully is allowed.

Solution

import urllib.request, base64

request = urllib.request.Request('http://www.pythonchallenge.com/pc/hex/unreal.jpg')
cred = base64.b64encode(b"butter:fly")
request.add_header("Authorization", "Basic %s" % cred.decode())
print(request.headers)
# {'Authorization': 'Basic YnV0dGVyOmZseQ=='}

response = urllib.request.urlopen(request)
print(response.headers)
# Content-Type: image/jpeg
# Content-Range: bytes 0-30202/2123456789
# Connection: close
# Transfer-Encoding: chunked
# Server: lighttpd/1.4.35

So it is a huge file(length of 2123456789) however only a small portion is served(0 to 30202). Try to get the content after that:

pattern = re.compile('bytes (\d+)-(\d+)/(\d+)')
content_range = response.headers['content-range']
(start, end, length) = pattern.search(content_range).groups()
request.headers['Range'] = 'bytes=%i-' % (int(end) + 1)
response = urllib.request.urlopen(request)
print(response.headers)
# {'Authorization': 'Basic YnV0dGVyOmZseQ=='}
# Content-Type: application/octet-stream
# Content-Transfer-Encoding: binary
# Content-Range: bytes 30203-30236/2123456789
# Connection: close
# Transfer-Encoding: chunked
# Server: lighttpd/1.4.35

print(response.read().decode())
# Why don't you respect my privacy?

So now the content between 30203 and 30236 is served, which is "Why don't you respect my privacy?"; continue for a few iterations:

pattern = re.compile('bytes (\d+)-(\d+)/(\d+)')
content_range = response.headers['content-range']
(start, end, length) = pattern.search(content_range).groups()

while True:
    try:
        request.headers['Range'] = 'bytes=%i-' % (int(end) + 1)
        response = urllib.request.urlopen(request)
        print(response.read().decode())
        print(response.headers)
        (start, end, length) = pattern.search(response.headers['content-range']).groups()
    except: 
        break

It prints:

Why don't you respect my privacy?

we can go on in this way for really long time.

stop this!

invader! invader!

ok, invader. you are inside now.

The last request ends at 30346.

Go to http://www.pythonchallenge.com/pc/hex/invader.html

Yes! that's you!

What about content after the length:

request.headers['Range'] = 'bytes=%i-' % (int(length) + 1)
response = urllib.request.urlopen(request)
print(response.headers)
print(response.read().decode())

Result:

Content-Type: application/octet-stream
Content-Transfer-Encoding: binary
Content-Range: bytes 2123456744-2123456788/2123456789
Connection: close
Transfer-Encoding: chunked
Server: lighttpd/1.4.35

esrever ni emankcin wen ruoy si drowssap eht

The content is reversed: "the password is your new nickname in reverse". The "nickname" is "invader", so password is "redavni".

Now "reverse" the search:

request.headers['Range'] = 'bytes=2123456743-'
response = urllib.request.urlopen(request)
print(response.headers)
print(response.read().decode())
Content-Type: application/octet-stream
Content-Transfer-Encoding: binary
Content-Range: bytes 2123456712-2123456743/2123456789
Connection: close
Transfer-Encoding: chunked
Date: Mon, 02 May 2016 18:12:45 GMT
Server: lighttpd/1.4.35


and it is hiding at 1152983631.

Then save it as a zip file:

request.headers['Range'] = 'bytes=1152983631-'
response = urllib.request.urlopen(request)

with open("level21.zip", "wb") as f:
    f.write(response.read())

Unzip it with the password("redavni").

Yes! This is really level 21 in here. And yes, After you solve it, you'll be in level 22!

Now for the level:

  • We used to play this game when we were kids
  • When I had no idea what to do, I looked backwards.

Next Level

Inside the zip file

results matching ""

    No results matching ""