Cyber attacks refer to any type of attack against computer information systems, infrastructure, computer networks or personal computer equipment. For computers and computer networks, destroying, exposing, modifying, disabling software or services, stealing or accessing any computer's data without authorization will be regarded as an attack in computers and computer networks.
In recent years, network attacks have occurred frequently, and Trojans, worms and blackmail software have emerged one after another on the Internet, which poses a serious threat to network security and even national security. In 2017, Wikileaks released the new network attack tools of the CIA and the NSA, including a large number of remote attack tools, vulnerabilities, network attack platforms and related attack description documents. At the same time, from some blogs, forums and open source websites, ordinary users can easily get different kinds of network attack tools. The openness of the Internet has greatly reduced the attack cost of network attackers. In may2017, the attack of the eternal blue blackmail virus broke out worldwide. The virus is a malicious code that attacks through the windows network sharing protocol and has the function of propagation and blackmail. It was confirmed by network security experts that the attacker initiated the network attack by modifying the "eternal blue" program in the network attack Arsenal leaked by NSA.