major global cyberattack began (Ukrainian companies were among the first to state they were being attacked), utilizing a new variant of Petya. On that day, Kaspersky Lab reported infections in France, Germany, Italy, Poland, the United Kingdom, and the United States, but that the majority of infections targeted Russia and Ukraine, where more than 80 companies were initially attacked, including the National Bank of Ukraine. ESET estimated on 28 June 2017 that 80% of all infections were in Ukraine, with Germany second hardest hit with about 9%. Russian president Vladimir Putin's press secretary, Dmitry Peskov, stated that the attack had caused no serious damage in Russia. Experts believed this was a politically-motivated attack against Ukraine, since it occurred on the eve of the Ukrainian holiday Constitution Day. Kaspersky dubbed this variant "NotPetya", as it has major differences in its operations in comparison to earlier variants. McAfee engineer Christiaan Beek stated that this variant was designed to spread quickly, and that it had been targeting "complete energy companies, the power grid, bus stations, gas stations, the airport, and banks". It was believed that the software update mechanism of —a Ukrainian tax preparation program that, according to F-Secure analyst Mikko Hyppönen, "appears to be de facto" among companies doing business in the country—had been compromised to spread the malware. Analysis by ESET found that a backdoor had been present in the update system for at least six weeks prior to the attack, describing it as a "thoroughly well-planned and well-executed operation". The developers of M.E.Doc denied that they were entirely responsible for the cyberattack, stating that they too were victims. On 4 July 2017, Ukraine's cybercrime unit seized the company's servers after detecting "new activity" that it believed would result in "uncontrolled proliferation" of malware. Ukraine police advised M.E.Doc users to stop using the software, as it presumed that the backdoor was still present. Analysis of the seized servers showed that software updates had not been applied since 2013, there was evidence of Russian presence, and an employee's account on the servers had been compromised; the head of the units warned that M.E.Doc could be found criminally responsible for enabling the attack because of its negligence in maintaining the security of their servers. Operation Petya's payload infects the computer's master boot record (MBR), overwrites the Windows bootloader, and triggers a restart. Upon startup, the payload encrypts the Master File Table of the