PSA: WannaCry cyber attack

A friendly advice to all of you using a computer running on Windows OS:
A ransomware known as "WannaCry" has been spreading across 150 countries, infecting over 230,000 computers.

WannaCry (or WannaCrypt, WanaCrypt0r 2.0, Wanna Decryptor or similar) is a ransomware program targeting Microsoft Windows. On Friday, 12 May 2017, a large cyber-attack using it was launched, infecting over 230,000 computers in 150 countries, demanding ransom payments in bitcoin in 28 languages. The attack has been described by Europol as unprecedented in scale. The attack affected Telefónica, FedEx, Deutsche Bahn, and the UK's National Health Service (NHS), among other corporate and governmental entities.

WannaCry is believed to use the EternalBlue exploit, which was developed by the U.S. National Security Agency (NSA) to attack computers running Microsoft Windows operating systems. Although a patch to remove the underlying vulnerability had been issued on 14 March 2017, users who delayed in applying security updates, or use unsupported versions of Windows, were left vulnerable. Microsoft has taken the unusual step of releasing updates for the unsupported Windows XP and Windows Server 2003 and patches for Windows 8 operating systems.

Shortly after the May 12 attack, several lines of code were found by an anti-malware researcher to function as a kill switch, and was activated by the researcher. This temporarily stopped the spreading of the virus. The code was initially reported in the media as a built-in kill switch; however, some analysts concluded that it was a programming mistake.

Source: Wikipedia

Basically:

If you never update Windows, it is highly recommended to do so in order to avoid the ransomware affecting and compromising your system.