This week, another ransomware virus called "Petya" infected computers around the world on a massive scale. In many ways, it is similar to the notorious WannaCry. The new ransomware, like its predecessor, uses the "EternalBlue" exploit, developed and used by the US NSA. Once the computer is infected, it encrypts all files on the device and kindly offers to buy a key to unlock it for $300 in bitcoins. Of course, there is no guarantee that the attacker will actually provide the necessary tools to decrypt the data on a PC.It is reported that the first to be affected by the Petya virus were companies from Ukraine. Thus, on the very first day of its spread, the malware infected numerous state-owned companies, commercial networks, infrastructure facilities, as well as a number of mobile phone operators. In addition, a number of large banks were also affected by the attack. In Transcarpathia, the branches of OTP bank and Ukrsotsbank were closed. At the same time, the press service of the Oshchadbank reported about the temporary restriction of availability of a number of services to customers for security purposes. The virus has struck some of the largest infrastructure facilities in the country. Thus, the state railway operator Ukrzaliznytsa and Kiev airport Boryspil have already been affected. True, the latter is still working in normal mode, but a warning about possible changes in the schedule has been published just in case. In addition, the two largest postal operators in Ukraine - "Ukrposhta" and "Nova Poshta" were also affected. But one of the most alarming was the news of the contamination of the Chernobyl nuclear power plant. In connection with this, workers were commanded to turn off computers and switch the monitoring of radiation levels to manual mode. To prevent contamination, the servers of the Kiev city administration website and the site of the Ukrainian Interior Ministry were shut down. As might have been expected, the Secretary of the National Security and Defense Council of Ukraine, Oleksandr Turchynov, has already discovered a "Russian trace" in this viral attack. Many Russian companies were also affected by the Petya virus. The largest of them were oil and gas giants Rosneft and Bashneft, Home Credit Bank, metallurgical company Evraz, as well as the Russian representative offices of such companies as Mars, Nivea, Mondelez International and many others. In addition, news about the virus affecting many large companies began to arrive from around the world. The Petya virus has already spread to France, the United States, Great Britain, Spain, Lithuania, India, and the Netherlands, while maintaining its "development" pace in new territories. Despite the fact that some experts insist that Petya only affects PCs running outdated versions of Windows, it is clearly not worth neglecting the security of even "10" users with all the latest updates. One of the most effective measures to prevent infection has been and remains cautious, especially when receiving suspicious links or downloading files from the Internet.