Lots of deep info here about whole classes of devices that are vulnerable to Mirai.
The fact that these things run telnet simply boggles the mind.
https://krebsonsecurity.com/2016/12/researchers-find-fresh-fodder-for-iot-attack-cannons/
If you're seeing this in your Analytics reports,
“Secret.ɢoogle.com You are invited! Enter only with this ticket URL. Copy it. Vote for Trump!”
and are sufficiently technical to do something about it, here's a great article on how to proceed.
http://blog.analytics-toolkit.com/2016/future-proofing-your-ga-vs-google-analytics-spam/
I've posted before on why HTTPS is important, and how to enable encryption.
There's even a free solution for SSL certs (Let's Encrypt).
Here's a very accessible explanation of the benefits:
https://blog.hubspot.com/marketing/enable-https-on-your-website#sm.000z8158sthpeky111x2e0m6s7erv
According to BadCyber.com, which first blogged about the emergence of the new Mirai variant, part of the problem is that Deutsche Telekom does not appear to have followed the best practice of blocking the rest of the world from remotely managing these devices as well.
https://krebsonsecurity.com/2016/11/new-mirai-worm-knocks-900k-germans-offline/