The number of connected devices is growing exponentially, with one billion new IoT devices expected to ship this year alone. As such, IPv4 addresses have been exhausted, but IPv6 is on deck to address this concern. Because IPv6 occupies such a relatively small space, Internet security implementations that take it into full consideration are also lagging. This leaves a lot of networks vulnerable to distributed denial of service (DDoS) attacks. DDoS attacks occur when Internet hackers use infected hosts to control connected devices remotely and make unwilling devices send malicious traffic to their target of choice.”]
Source: https://www.darkreading.com/attacks-breaches/ipv6-and-the-growing-ddos-danger