solver.py

import sys
from pwn import * 

CONNECTION_TIMEOUT = 5 
IMAGE_NAME = 'cur_round_image.png'

def SaveImage( Filename, Data ):
	fd = open( Filename, 'wb' )
	fd.write( Data )
	fd.close()

def GetTextFromImage( Filename ):
	p = process( [ "gocr", Filename ] )
	text = p.recvline().strip()
	p.close()

	return text

if __name__ == "__main__":

	if len( sys.argv ) > 2:
		host = sys.argv[ 1 ]
		port = int( sys.argv[ 2 ] )
	else:
		print "Usage: python " + sys.argv[ 0 ] + " <host> <port>"
		sys.exit( -1 )

	while 1:
		sock = remote( host, port )

		sock.recvuntil( "(Y/N): " ) # skip banner and menu

		sock.send( "Y\n" )
		
		while 1:
			ImageData = sock.recvline().strip()
			if "CupCTF" in ImageData:
				print ImageData
				sys.exit( -1 )

			sock.recvuntil( ": " )

			ImageData = ImageData.decode( 'hex' )
			SaveImage( IMAGE_NAME, ImageData )

			answer = GetTextFromImage( IMAGE_NAME )
			
			#print "answer = ", answer

			sock.send( answer + '\n' )

			result = sock.recvline()	

			if "Correct" in result:
				continue 
			else:
				sock.close()
				break