Want to find new WhatsApp groups?
Reporter Jordan Wildon has discovered hundreds of thousands of private groups through the search engine thanks to public invitation links. Not all were created with the intention that anyone could join them after a simple search.
As a Facebook spokesperson explained to Motherboard, administrators of a WhatsApp group can invite others to join the group by generating an invitation link. When this is shared on a publicly accessible website, search engines such as Google can index it, which means that anyone could reach it with the right search.
If you search for inurl:chat.whatsapp.com site:whatsapp.com in Google, the search engine returns about 470,000 results. Most are groups you can join with a couple of clicks, including several groups with "child pornography" in the name. You can't see what's been posted in them before, but you can see the participants' phone numbers.
In a message sent in November to a user seeking a financial reward for discovering the problem, a Facebook security employee responded that there was no problem. According to this person, it is intentional that WhatsApp's invitation links are accessible to everyone, but it is "a surprise" that they are being indexed by Google.
Google's Danny Sullivan explained that there are tools for sites such as the WhatsApp website which can block content from appearing in search engine results. If Facebook simply set the robots.txt file on its website to "Disallow" or added a "noindex" meta tag to its source code, Google would not display the WhatsApp group invitation links on its results page, a potential privacy issue for users. However, Facebook has not done anything since November.
If you have a WhatsApp group with an invitation link and suddenly a stranger walks in, you probably know why. If you don't, but want your groups to be completely private, make sure you don't post the link on the Web.