[ad_1]
A serious security flaw found in WhatsApp has exposed the phone numbers of 3.5 billion users around the world. This is considered to be one of the biggest data leak cases ever recorded. The matter of concern is that Meta (Facebook) was being warned about this weakness since 2017, but it took eight years to fix it.
This flaw was in the Contact Discovery Feature of WhatsApp. When someone searches for a phone number in the app, WhatsApp tells whether the number is available on the service or not, and also shows public information like profile photo and status text.
Security researchers from the University of Vienna, Austria scanned a large number of phone numbers using this feature. With the help of just 5 WhatsApp accounts and one server, they checked 63 billion possible numbers and found 3.5 billion active WhatsApp numbers, that too at a speed of 100 million numbers per hour.
For research, he generated real phone numbers of 245 countries with a tool called ‘libphonegen’ and used WhatsApp’s XMPP protocol.
What was included in the leaked information?
According to the researchers, they obtained a lot of information from 56.7% of the accounts, which included phone numbers, profile photos, about text, encryption keys (KEYS), timestamps and in some cases, linked social profiles.
The most surprising thing was that religious, political or personal information was found written in the ‘About’ section of 29.3% of the users.
Duplicate encryption was found in approximately 29 lakh accounts, which could jeopardize WhatsApp’s secure end-to-end encryption. In one serious example, 20 US numbers were found to have the same KEY containing zeros, raising suspicions of fraud.
What is the answer to Meta?
Meta acknowledged this report in April 2025 and released a rate-limiting patch in October 2025. The company said that the leaked data was already ‘public’, the chats were secure, the anti-scraping system is being strengthened. However, experts say the risk still remains, especially for WhatsApp Business accounts because they keep more information public.
Security Tips for Users
- Set your WhatsApp profile to Private (Contacts only)
- Do not write personal information in ‘About’
- Beware of unknown messages or calls
- Check Privacy Settings in WhatsApp from time to time.
[ad_2]
