This is scary. Maybe you've heard of Shodan before; I know I hadn't.
Shodan (if you don't want to track this down) maps physical computers connected on the Internet. Think of it as search for computers rather than web pages. This makes it the tool of choice for finding, say, routers with the default login/password still set. Then you know which IP addresses to mount an attack on.
Fact is, there are a zillion ways for the Bad Guys to attack you. One thing you can do (in addition to using Shodan to search your own net for unprotected hardware) is to consider using CodeMeter to ensure code integrity on your embedded systems. In addition to preventing software theft or reverse engineering, encrypting the code with AxProtector and requiring CodeMeter to decrypt it prevents any bits from being changed. Unless the code remains unchanged it won't decrypt. So no chance that an intruder can install any malicious payload.
Here you can see some of the different (non USB) form factors including PC Card, PC Express, SD, Micro SD, and Compact Flash. You can also get CodeMeter on an ASIC wafer or a wee small board to solder into your system. Most of these are optionally available with additional flash RAM--up to 16GB for some.
All these are functionally the same: they all have the SmartCard chip, our firmware, and memory and they all work exactly the same on Windows, Linux, even VxWorks. Of course we support MacOS but that's not applicable to embedded applications that I'm aware of.
For more information on all the CodeMeter variants click the button below.