Comcast / Xfinity does have security. (so does Verizon and smaller ISPs today)
A total home security solution
That said had it installed recently in one family members home.
It is not personally what I would want for my home.
In addition to remotely arming and disarming your system with the XFINITY Home app, you can also look after and control your home from anywhere. With additional equipment, get live video monitoring so you can see that your kids got home safely, control your thermostat and turn on lights so you never come home to a dark house again, and much more.
Think it starts around $29.99 for one year with a two year contract. Even better bundle it with your telephone and televison and get even a better deal.