A wave of cyber-attacks hit Romania on Friday and Saturday. The websites of the government, the National Cyber Security Directorate, the Defense Ministry, the Border Police, the National Rail Company and certain commercial banks were taken down. The attack was claimed by the pro-Russian hacker network Killnet, in response to Romania’s support actions for Ukraine. Killnet hackers this month also attacked institutions in Estonia, Poland, the Czech Republic, the United States, as well as NATO websites. Experts say this was a DDoS attack, which is a malicious attempt to flood a network or an online service with HTTP requests, thus rendering them unavailable to their users.