On August 20, the online course registration server of Korea University (KU) was temporarily paralyzed due to outer Distributed Denial-of-Service (DDoS) attacks. As a form of a cyber-attack that renders the network unavailable through flooding numerous false Internet protocols (IP), it thereby overloads the entire network. These attacks first appeared at 10 A.M. when the sophomore students were scheduled to register.

Consequently, as similar attacks hindered the registration process, the registration was postponed to August 24 for sophomore students and 25 for the freshmen. The Office of Academic Affairs of KU announced that it would do its best to devise extensive solutions to fend off DDoS attacks. It further instructed the students to consistently reconnect to the server even if it was not stable at the time of the rescheduled registration.

On August 24 and 25, course registration was able to take place as planned as the school has successfully dealt with the attacks. Nonetheless, the server was unstable to some students and produced slight delays as outer attacks continued.