This seems a bit of a problematic method of gaining control, given the numbers involved its likely that a large number of folks could be duped into undertaking some of the actions necessary to hijack their router but overall the method is not ever going to reach anything like saturation levels as it involves so many favourable conditions to acheive success.
I could give out the old advice regarding checking for and deploying the latest firmware updates etc but I suspect in many cases such an update has not yet been released and so I fell the better advice is to steer clear of dodgy pop-ups dodgy web sites (avoid those without HTTPS) and give up using that crapware called email