"The secret group of French state hackers that managed to infiltrate tens of thousands of secure and encrypted phones in Europe used an Android vulnerability first detected in 2017, as CW has learned. For two years, a serious security vulnerability, known as the Bad Binder bug, remained unpatched on 2.5 billion phones, leaving users at maximum risk. This vulnerability allowed cyber spies to take full control of infected phones and copy or modify users' data, programs, and files at will."