Oflate there has been a lot of interest in Microcontroller community about security with ARM TrustZone for MCUs. TrustZone is deemed to protect MCUs against software attacks. My question is what are the ways a malicious code can even enter an MCU?

 

 

The answer is simple.
Let us begin at square one.

Malicious code can enter any MCU at

1) chip fabrication, at the foundry during the manufacturing process - likelihood, extremely low.

2) during code development, from rogue assembler or compiler - likelihood, very low.

3) during code development, from third party libraries or rogue code (in-house or external) - likelihood, low.

4) during firmware testing, while testing via external connections, LAN, WAN, WiFi, internet - likelihood, possible.

5) during deployment, with live connection to LAN, WAN, WiFi, internet - likelihood, HIGH.

6) If you allow firmware upgrade via USB, internet, etc. - likelihood, HIGH.

If your MCU has zero connection to LAN, WAN, WiFi, internet - likelihood of infection, ZERO.

 

Thanks MrChips.

What is the likelihood of malicious code entering via 802.15.4 networks?

 

If the PAN (personal area network) is not connected to the larger internet then the likelihood is very low.
It would require an intentional malicious hack into your network by a disgruntled employee, associate, or spy.

If your data communications never alters the embedded MCU firmware then the likelihood is next to zero.

 

One possibility is a dual CPU like PSOC 6, it has security features and
dual CPU can be designed to cross check on state of cpu using external
com.

http://www.cypress.com/products/32-bit-arm-cortex-m4-psoc-6

Videos http://www.cypress.com/products/32-bit-arm-cortex-m4-psoc-6

Security - http://www.cypress.com/products/32-bit-arm-cortex-m4-psoc-6


Regards, Dana.

 

Most likely the controller firmware won't be directly attacked. Bugs in the firmware and/or networks will be used to attack systems of value with the controller as an attact vector.
http://www.businessinsider.de/hacke...meter-in-the-lobby-fish-tank-2018-4?r=UK&IR=T

Nicole Eagan, the CEO of cybersecurity company Darktrace, told the WSJ CEO Council in London on Thursday: "There's a lot of internet of things devices, everything from thermostats, refrigeration systems, HVAC [air conditioning] systems, to people who bring in their Alexa devices into the offices. There's just a lot of IoT. It expands the attack surface and most of this isn't covered by traditional defenses."

Eagan gave one memorable anecdote about a case Darktrace worked on where an unnamed casino was hacked via a thermometer in a lobby aquarium.

"The attackers used that to get a foothold in the network. They then found the high-roller database and then pulled that back across the network, out the thermostat, and up to the cloud," she said.