Comparing Alternatives to Measure the Impact of DDoS Attack Announcements on Target Stock Prices

The attack intensity of distributed denial of service (DDoS) attacks is increasing every year. Botnets based on internet of things (IOT) devices are now being used to conduct DDoS attacks. The estimation of direct and indirect economic damages caused by these attacks is a complex problem. One of the indirect damage of a DDoS attack can be on the market value of the victim firm. In this article we analyze the impact of 45 different DDoS attack announcements on victim's stock prices. We find that previous studies have a mixed conclusion on the impact of DDoS attack announcements on the victim's stock price. Hence, in this article we evaluate this impact using three different approaches and compare the results. In the first approach, we use the assume the cumulative abnormal returns to be normally distributed and test the hypothesis that a DDoS attack announcement has no impact on the victim's stock price. In the latter two methods, we do not assume a distribution and use the empirical distribution of cumulative abnormal returns to test the hypothesis. We find that the assumption of cumulative abnormal returns being normally distributed leads to overestimation/underestimation of the impact. Finally, we analyze the impact of DDoS attack announcement on victim's stock price in each of the 45 cases and present our results.