Protostar - Net #0

About:

This level takes a look at converting strings to little endian integers. (link)


Source Code:

Solution:

For net0, they want you to connect to the background process running on port 2999, read the integer contained in the string it sends, and send it back as a little-endian 32-bit integer.

I wrote a quick python script to do this:

#!/usr/bin/env python
#

import socket
import struct

HOST = "127.0.0.1"
PORT = 2999

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

s.connect((HOST, PORT))

msg = s.recv(1024)
print msg

value = int(msg.split("'")[1])
print "parsed value:", value

to_send = struct.pack("I", value) + "\n"
s.sendall(to_send)
print "sending:", to_send

print "response:", s.recv(1024)


Running it gives the following output:

user@protostar:/opt/protostar/bin$ python /tmp/net0.py
Please send '884996042' as a little endian 32bit int

parsed value: 884996042
sending: ???4

response: Thank you sir/madam