Code Blue, issue 1.0

Microphones that “hear” light; microprocessors that “tell” us
secrets; self-driving cars that “see” fake objects; sensors that
“feel” the wrong temperature. Our devices are under attack in
new, increasingly sophisticated ways. Security researchers at CSE
are exploring the limits of hardware and finding new, sobering
vulnerabilities in our computers and homes.
Where does “computer” end, and “real world” begin? This line,
separated so firmly in our minds by apps and user interfaces, is
finer than it appears.
Our computers aren’t bounded by programs, but by physics: the
electrons flowing between a microprocessor and memory; device
ports and wireless receivers; microphones, wires, speakers, screens,
and other channels along which signals travel or cross from one
medium into another. While programmers often categorize hardware
as externalities that they don’t have to worry about, their programs
are ultimately running on real-world machines with real-world
imperfections.
With the widespread adoption of smart speakers, security cameras
and vision systems, and embedded systems, the distinction gets even
hairier — computers are suddenly a lot more perceptive than we’re
used to, and the edges between computer and reality become viable
channels for input. In tandem with this, microprocessors themselves
have turned increasingly to clever tricks to achieve better performance
without considering the observable side effects that start to manifest
in the real world.
Microphones that hear light
A physics quirk discovered in the labs
of Profs. Kevin Fu and Daniel Genkin
led to a unique new hack: remotely
controlling smart speakers with a
laser. | Photo: Joseph Xu
With this complexity in function come new avenues for hacking attacks.
In a hypothetical closed computer, walled off from real-world physics,
the weak points are code and human behavior. Trick someone
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