Facebook - Is a company that has been riddled privacy issues and concerns of late. After the Cambridge Analytica incident, Facebook lost many subscribers, to say the least. The two other limbs of the company, WhatsApp and Instagram were spared. However, there has been a new WhatsApp privacy issue found.
The security researcher, Athul Jayaram, has found that your WhatsApp associated phone number could end up on Google's search engine. Jayaram then shared what he had learned online. According to him, when someone uses the Click to Chat option on their website to start a messaging session, the associated phone number is revealed in plain text.
Google then indexes the code and displays the mobile number in its search results. The mobile number is visible in plain text in the URL. Anyone who manages to get hold of the URL will know your number and you cannot revoke it.
The URL string your phone number is revealed in is (https://wa.me/<phone_number>). In effect, the number is leaked. The "wa.me" domain is owned and maintained by WhatsApp according to WHOIS records.
When asked to comment, WhatsApp had said that their Click to Chat feature "lets users create a URL with their phone number so that anyone can easily message them, is used widely by small and microbusinesses around the world to connect with their customers,”.
The researcher, Jayaram had recommended that WhatsApp encrypt their user mobile numbers and add a robots.txt file in order to stop bots from crawling the domain Unfortunately they have not done that yet.