Just found this. Seems hackers can get to the router's settings. Without searching I don't have the info of how to block this vulnerable TCP port number: 32764. Just a post to warn of possible security breach.
There's an update in the article, " Update: Vanderbeken reports some routers have the backdoor open to the Internet side as well, leaving them vulnerable to remote attack." So not confined to just a local network on some routers.
My old router, a Netgear DGN2200v3, is on that list but, I suspect the chances of actually being hacked in this way are pretty remote. Having recently got fibre we are now on a BT HomeHub 5 which is, I believe, made by Hauwei.