WHATSAPP SECURITY FLAW EXPOSES 3.5B USERS' DATA FROM ‘BASIC PUBLICLY AVAILABLE INFORMATION'

Summary from the TLDR InfoSec newsletter

Austrian researchers discovered that all 3.5B WhatsApp users can be enumerated at a rate of 100M users per hour. The researchers used the WhatsApp Web interface to bulk add users and phone numbers and were able to extract phone numbers for all users, profile photos for 57% of users, and profile text for 27%. Meta implemented rate limiting to address this issue, but also stated that the data exposed was basic publicly available information.