Computer threats and countermeasures in modern world

The thesis examines computer threats and countermeasures on modern world focusing on the use of personal computer and mobile devices. As the issue Is wide and complex such a focus is justified for this thesis. The impact of cyberattacks and cybercrimes is significant for computer users and through them to businesses and society. Some estimates suggest that the damage related to cy- bercrime is growing rapidly and is projected to be USD 6 trillion globally in 2021. Six main types of computer attacks can be identified: backdoor, virus, denial of service at- tack, distributed denial of service attack, browser hijacking and eavesdropping of man-in- the middle attack Individual PC and mobile device users operate in different systems and are using different operating systems and vulnerabilities vary accordingly. The thesis looks systematically at the vulnerabilities and counter-measures is different situations. It is important to note that some studies suggest that some 70% of computer attacks originate from emails and their attachments. The computer threats and vulnerabilities are a serious issue in the modern world which is increasingly relying on IT-solutions in providing services for businesses and public and in the transformation to the digital economy and society. The damage caused by cyberat- tacks and crimes is already very high and on increase. At the same time the cyberattacks and cybercrimes are slowing down and impeding the digitalisation and all the efficiency gains and other benefits it can bring about. Also risks to security are evident and felt already. The stakes are high, the awareness is still low and available countermeasures and knowledge of them is not fully utilise