[empath75]

There are lots of ways to get inside a network besides going through open nat ports. If there's a web interface, you could pop that, or go through an infected pc, etc. Once you're in the network, you can hit all the ports you want inside it.

[dimino]

But that's not how it's happening. These IoT devices are being granted IP addresses, somehow. Mirai is scanning the web and blindly trying telnet, and if it works, it tries these password combos. It doesn't do anything even remotely sophisticated to navigate a network.

[glennos]

Agree, seems bizarre but sounds like sloppy device config.

https://news.ycombinator.com/item?id=12765265