The router is the gateway to the Internet from your home or business. Until recently many commercially available routers have had limited security features. The steps that you can take include enable automatic firmware update (the software for the router) and changing the default passwords. You should also change the administrator login if you have that option.
If you haven’t upgraded your router for some time then it would be a good idea to do so now. You might also want to consider replacing the router that was issued by your ISP if you have that option. ISPs that provide the option of Bring Your Own (BYO) router are usually preferable if you have that option and have the technical knowledge to configure it.
Small businesses should consider engaging a IT security or network professional to review their network and provide advice on the most suitable hardware and configuration.