“An advanced cyber actor” exploited a major vulnerability of Facebook’s WhatsApp online messaging application, which managed to install a clandestine monitoring program on phones and other devices, said  the company , according to Sky News. All users are advised to do UPDATE with the latest version!

Hackers used the voice call function of the application to call the victim, and even if they did not respond to the call, a clandestine monitoring program was installed. The company’s security team has announced human rights groups, the US Department of Justice and security firms shortly after they noticed the vulnerability.

“The attack has all the hallmarks of a private company working with governments to provide spyware programs that take control of mobile phone operating system functions,” said a statement released  by WhatApp on Monday.

Vulnerability was used on May 12 in a cyber attack targeting the mobile phone of a lawyer in the UK, the Financial Times reported. The lawyer, whose identity has not been revealed, is involved in a lawsuit against the NSO, filed by a group of Mexican journalists and a Saudi dissident.

More than 1.5 billions people in the whole world and more than half of the people which have a mobilephone in Romania are using WhattsApp.