On 27 June 2017, a massive cyber attack hit Ukraine on the eve of a Constitution Day, a state holiday. The virus disguised as a ransomware, a malware blocking access to the computer’s data and demanding money to release it. However, it turned out later that encrypted data cannot be decrypted back. The attack targeted the Microsoft Windows PCs in Ukrainian banks, companies, and organizations. The virus began spreading by exploiting an update of a Ukrainian accounting software package. Another wave of infections was caused by a targeted phishing mailout. Later, the attack spread to more than 60 countries.
