Remember Mirai? This four-year old botnet was the scourge of the internet and used as the launching pad for numerous DDoS attacks. It continues to be the basis for new attacks, and I blog about this for Avast here. There are several mitigation measures you can take, including  using a free tool from F-Secure that can check your router for any potential weaknesses. You might also use this to put a more complete program in place to ensure all critical network infrastructure has appropriately complex and unique passwords.