System Bits: March 21

Sensors vulnerable to sonic cyber attacks
According to University of Michigan researchers, sound waves could be used to hack into critical sensors in a wide range of technologies including smartphones, automobiles, medical devices and IoT devices.

New research calls into question the longstanding computer science tenet that software can automatically trust hardware sensors, which feed autonomous systems with fundamental data they need to make decisions, the team said.

The work showed that inertial sensors, also known as capacitive MEMS accelerometers, which measure the rate of change in an object’s speed in three dimensions, can be tricked.

Kevin Fu, U-M associate professor of computer science and engineering led the team that used precisely tuned acoustic tones to deceive 15 different models of accelerometers into registering movement that never occurred. This served as a backdoor into the devices—enabling the researchers to control other aspects of the system.
The key to all of this is the fact that all accelerometers have an analog core—a mass suspended on springs — and when the object the accelerometer is embedded in changes speed or direction, the mass moves accordingly. The digital components in the accelerometer process the signal and ferry it to other circuits.

Fu asserted, “Analog is the new digital when it comes to cybersecurity. Thousands of everyday devices already contain tiny MEMS accelerometers. Tomorrow’s devices will aggressively rely on sensors to make automated decisions with kinetic consequences.”

This work could be vital to especially since autonomous systems like package delivery drones and self-driving cars base their decisions on what their sensors tell them, and if autonomous systems can’t trust their senses, then the security and reliability of those systems will fail.

The trick that the researchers introduced exploits the same phenomenon behind the legend of an opera singer breaking a wine glass. Key to that process is hitting the right note: the glass’ resonant frequency. To that end, the team identified the resonant frequencies of 20 different accelerometers from five different manufacturers. Then instead of shattering the chips, they tricked them into decoding sounds as false sensor readings that they then delivered to the microprocessor.

Michigan Engineering researchers used a malicious music file to hack into a Samsung Galaxy S5, coaxing its accelerometer to read out the word WALNUT. While the attack itself doesn’t sound all that frightening, in principle, it revealed a major security hole in certain commonplace hardware sensors. (Source: University of Michigan)

They noted additional vulnerabilities in these systems as the analog signal was digitally processed. Digital low pass filters that screen out the highest frequencies, as well as amplifiers, haven’t been designed with security in mind, and in some cases, they inadvertently cleaned up the sound signal in a way that made it easier for the team to control the system.

The researchers have recommendations to adjust hardware design to eliminate the problems. As well, they’ve developed two low-cost software defenses that could minimize the vulnerabilities, and alerted manufacturers to these issues.

Computer vision technology aids in biomedical modeling
By leveraging a new computer vision technique with existing data, Stanford University researchers have created a 3D computer reconstruction of a patient’s bladder.

Audrey Bowden, assistant professor in the Department of Electrical Engineering at Stanford University noted that the beauty of this project is that data that doctors are already collecting with endoscopes can be used.

Given that bladder cancer has among the highest recurrence rates of any cancer — from 50 percent to 70 percent of tumors return after removal — being able to see each patient’s bladder as a 3D model could improve surgical planning and monitor cancer recurrence.

Audrey Bowden, assistant professor in the Department of Electrical Engineering, is a co-senior author of a paper about modeling the bladder with advanced computer imaging technology. (Source: Stanford University)

One of the technique’s advantages is that doctors don’t have to buy new hardware or modify their techniques significantly because through the use of advanced computer vision algorithms, the research team reconstructed the shape and internal appearance of a bladder using the video footage from a routine cystoscopy, which would ordinarily have been discarded or not recorded in the first place.

Although the team developed the technique for the bladder, it could be applied to other hollow organs where doctors routinely perform endoscopy, including the stomach or colon.

Next-generation flexible electronics
Georgia Institute of Technology researchers are working to lay the groundwork for manufacturing next-generation flexible electronics, which have the potential to make an impact on industries ranging from health care to defense.

Four projects will take place over the next two years, backed by NextFlex, the Flexible Hybrid Electronics Manufacturing Innovation Institute, a group of private companies, universities, several state and local governments and not-for-profit organizations with a mission to advance flexible electronics manufacturing in the United States.

Researchers at Georgia Tech are partnering with Boeing, Hewlett Packard Enterprises, General Electric, and DuPont as well other research institutions such as Binghamton University and Stanford University on the projects.

Flexible electronics — circuits, and systems that can be bent, folded, stretched or conformed without losing their functionality — are often created by machines that can print components such as logic, memory, sensors, batteries, antennas, and various passives using conductive ink on flexible surfaces. Combined with low-cost manufacturing processes, flexible hybrid electronics could unlock new opportunities for a wide range of electronics used in the health care, consumer products, automotive, aerospace, energy and defense sectors — and have the potential to positively impact some of society’s greatest challenges.

The area of flexible hybrid electronics has a unique appeal because of the inexpensive nature of printed electronics and the availability of a wide-range of substrate materials in large panel forms.

In one of the projects, Boeing will partner with Georgia Tech researchers to create a flexible array antenna that could be incorporated into a plane fuselage.

In another project, Georgia Tech researchers will partner with Binghamton University and DuPont to perform a range of tests on flexible electronics to gauge how the mechanical and electrical characteristics will change under repeated bending, stretching, and twisting over a wide range of temperatures.

In a third project headed by Hewlett Packard Enterprises in partnership with Georgia Tech, Stanford University, and the University of California – Santa Barbara, the team will develop process-design kits (PDK) for flexible electronics.

In the fourth project, led by Binghamton University, Georgia Tech researchers will examine the reliability of wearable human health and performance monitoring devices through physics-of-failure models.

A Georgia Tech researcher displays the flexibility of a new class of electronics. (Source: Georgia Tech)