MEMS Accelerometer Hardware Design Flaws

[rv8ch]

I hope this does not trigger an expensive recall. I'm struggling to assess the possible impact here on experimental aviation, but for the big iron, could be a security risk.

https://ics-cert.us-cert.gov/alerts/ICS-ALERT-17-073-01

NCCIC/ICS-CERT is aware of public reporting of hardware design flaws in some capacitive micro-electromechanical systems (MEMS) accelerometer sensors, which are produced by the following manufacturers: Robert Bosch GmbH, STMicroelectronics, InvenSense Inc., Analog Devices Inc., and Murata Manufacturing Company.
According to public reporting, the design flaws may be exploitable by playing specific acoustic frequencies in close proximity to devices containing embedded capacitive MEMS accelerometer sensors. At a specific acoustic frequency it may be possible to induce a vibration within vulnerable accelerometers to alter the sensors? output in a predictable way. The impact of exploitation would be dependent on the function and operation of host devices, but it is understood that during an attack it may be possible to render affected sensors inoperable.

 

[DaleB]

It's kind of the nature of the beast, I think. It doesn't seem like that's as much a "design flaw" as a characteristic of the technology. This seems a little like saying the design flaws of a magnetic compass can be exploited by placing magnets in close proximity to alter the output in a predictable way.

It's always good practice not to rickroll your EFIS.

 

[SMRacer]

It's always good practice not to rickroll your EFIS.

And now we can positively determine the popularity of the VAF web site by watching the Google search trends for "rickroll".

 

[N402RH]

Looking forward to all the tech support calls we are going to get on this one.

Rob Hickman
N402RH RV-10

 

[PilotjohnS]

Really?

In our little RV world, i will be surprised if this amount to anything. Our avionics are in such a benign environment I cant se this being a concern. But if anybody is scared, and wants to sell me thier NIB G3x for half price, i will take it off your hands and worry about this recall for you.

 

[unitink72]

Big iron

A fun experiment, but not worth much to a bad guy in the real world. These inertial boxes live in the bowels of the beast - inaccessible to passengers. Also (in fly by wire systems anyway) there are multiple of these sensors, often with one from a different manufacturer. Their outputs are constantly being compared with one another.

A large deviation from one box that isn't matched by the others quickly gets that box condemned.

 

[fl-mike]

In our little RV world, i will be surprised if this amount to anything. Our avionics are in such a benign environment I cant se this being a concern. But if anybody is scared, and wants to sell me thier NIB G3x for half price, i will take it off your hands and worry about this recall for you.

Actually, our loud and shaky craft are ripe environments for this issue.
Inertial sensors, especially consumer grade MEMS are full of interesting error sources. Non-linear temperature related bias shift, bias hysteresis, vibration rectification, random walk, etc. Some are fairly easy to calibrate out, others, not so much. I have some experience in this area. As in most cases in life, you pay for performance, and/or you do a lot of calibrating ($).
And yeah, loud noise can cause one (competitor's) standby to get the leans. Or so I hear...