Entries Tagged "sensors"

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Side Channels Are Common

Really interesting research: “Lend Me Your Ear: Passive Remote Physical Side Channels on PCs.”

Abstract:

We show that built-in sensors in commodity PCs, such as microphones, inadvertently capture electromagnetic side-channel leakage from ongoing computation. Moreover, this information is often conveyed by supposedly-benign channels such as audio recordings and common Voice-over-IP applications, even after lossy compression.

Thus, we show, it is possible to conduct physical side-channel attacks on computation by remote and purely passive analysis of commonly-shared channels. These attacks require neither physical proximity (which could be mitigated by distance and shielding), nor the ability to run code on the target or configure its hardware. Consequently, we argue, physical side channels on PCs can no longer be excluded from remote-attack threat models.

We analyze the computation-dependent leakage captured by internal microphones, and empirically demonstrate its efficacy for attacks. In one scenario, an attacker steals the secret ECDSA signing keys of the counterparty in a voice call. In another, the attacker detects what web page their counterparty is loading. In the third scenario, a player in the Counter-Strike online multiplayer game can detect a hidden opponent waiting in ambush, by analyzing how the 3D rendering done by the opponent’s computer induces faint but detectable signals into the opponent’s audio feed.

Posted on January 23, 2024 at 7:09 AM • View Comments

Breaking Laptop Fingerprint Sensors

They’re not that good:

Security researchers Jesse D’Aguanno and Timo Teräs write that, with varying degrees of reverse-engineering and using some external hardware, they were able to fool the Goodix fingerprint sensor in a Dell Inspiron 15, the Synaptic sensor in a Lenovo ThinkPad T14, and the ELAN sensor in one of Microsoft’s own Surface Pro Type Covers. These are just three laptop models from the wide universe of PCs, but one of these three companies usually does make the fingerprint sensor in every laptop we’ve reviewed in the last few years. It’s likely that most Windows PCs with fingerprint readers will be vulnerable to similar exploits.

Details.

Posted on November 29, 2023 at 7:09 AM • View Comments

Smartphones and Civilians in Wartime

Interesting article about civilians using smartphones to assist their militaries in wartime, and how that blurs the important legal distinction between combatants and non-combatants:

The principle of distinction between the two roles is a critical cornerstone of international humanitarian law­—the law of armed conflict, codified by decades of customs and laws such as the Geneva Conventions. Those considered civilians and civilian targets are not to be attacked by military forces; as they are not combatants, they should be spared. At the same time, they also should not act as combatants—­if they do, they may lose this status.

The conundrum, then, is how to classify a civilian who, with the use of their smartphone, potentially becomes an active participant in a military sensor system. (To be clear, solely having the app installed is not sufficient to lose the protected status. What matters is actual usage.) The Additional Protocol I to Geneva Conventions states that civilians enjoy protection from the “dangers arising from military operations unless and for such time as they take a direct part in hostilities.” Legally, if civilians engage in military activity, such as taking part in hostilities by using weapons, they forfeit their protected status, “for such time as they take a direct part in hostilities” that “affect[s] the military operations,” according to the International Committee of the Red Cross, the traditional impartial custodian of International Humanitarian Law. This is the case even if the people in question are not formally members of the armed forces. By losing the status of a civilian, one may become a legitimate military objective, carrying the risk of being directly attacked by military forces.

Posted on June 9, 2022 at 6:22 AM • View Comments

Wi-Fi Devices as Physical Object Sensors

The new 802.11bf standard will turn Wi-Fi devices into object sensors:

In three years or so, the Wi-Fi specification is scheduled to get an upgrade that will turn wireless devices into sensors capable of gathering data about the people and objects bathed in their signals.

“When 802.11bf will be finalized and introduced as an IEEE standard in September 2024, Wi-Fi will cease to be a communication-only standard and will legitimately become a full-fledged sensing paradigm,” explains Francesco Restuccia, assistant professor of electrical and computer engineering at Northeastern University, in a paper summarizing the state of the Wi-Fi Sensing project (SENS) currently being developed by the Institute of Electrical and Electronics Engineers (IEEE).

SENS is envisioned as a way for devices capable of sending and receiving wireless data to use Wi-Fi signal interference differences to measure the range, velocity, direction, motion, presence, and proximity of people and objects.

More detail in the article. Security and privacy controls are still to be worked out, which means that there probably won’t be any.

Posted on April 5, 2021 at 6:15 AM • View Comments

Fingerprinting iPhones

This clever attack allows someone to uniquely identify a phone when you visit a website, based on data from the accelerometer, gyroscope, and magnetometer sensors.

We have developed a new type of fingerprinting attack, the calibration fingerprinting attack. Our attack uses data gathered from the accelerometer, gyroscope and magnetometer sensors found in smartphones to construct a globally unique fingerprint. Overall, our attack has the following advantages:

  • The attack can be launched by any website you visit or any app you use on a vulnerable device without requiring any explicit confirmation or consent from you.
  • The attack takes less than one second to generate a fingerprint.
  • The attack can generate a globally unique fingerprint for iOS devices.
  • The calibration fingerprint never changes, even after a factory reset.
  • The attack provides an effective means to track you as you browse across the web and move between apps on your phone.

* Following our disclosure, Apple has patched this vulnerability in iOS 12.2.

Research paper.

Posted on May 22, 2019 at 6:24 AM • View Comments

Tracking People Without GPS

Interesting research:

The trick in accurately tracking a person with this method is finding out what kind of activity they’re performing. Whether they’re walking, driving a car, or riding in a train or airplane, it’s pretty easy to figure out when you know what you’re looking for.

The sensors can determine how fast a person is traveling and what kind of movements they make. Moving at a slow pace in one direction indicates walking. Going a little bit quicker but turning at 90-degree angles means driving. Faster yet, we’re in train or airplane territory. Those are easy to figure out based on speed and air pressure.

After the app determines what you’re doing, it uses the information it collects from the sensors. The accelerometer relays your speed, the magnetometer tells your relation to true north, and the barometer offers up the air pressure around you and compares it to publicly available information. It checks in with The Weather Channel to compare air pressure data from the barometer to determine how far above sea level you are. Google Maps and data offered by the US Geological Survey Maps provide incredibly detailed elevation readings.

Once it has gathered all of this information and determined the mode of transportation you’re currently taking, it can then begin to narrow down where you are. For flights, four algorithms begin to estimate the target’s location and narrows down the possibilities until its error rate hits zero.

If you’re driving, it can be even easier. The app knows the time zone you’re in based on the information your phone has provided to it. It then accesses information from your barometer and magnetometer and compares it to information from publicly available maps and weather reports. After that, it keeps track of the turns you make. With each turn, the possible locations whittle down until it pinpoints exactly where you are.

To demonstrate how accurate it is, researchers did a test run in Philadelphia. It only took 12 turns before the app knew exactly where the car was.

This is a good example of how powerful synthesizing information from disparate data sources can be. We spend too much time worried about individual data collection systems, and not enough about analysis techniques of those systems.

Research paper.

Posted on December 15, 2017 at 6:18 AM • View Comments

Websites Grabbing User-Form Data Before It's Submitted

Websites are sending information prematurely:

…we discovered NaviStone’s code on sites run by Acurian, Quicken Loans, a continuing education center, a clothing store for plus-sized women, and a host of other retailers. Using Javascript, those sites were transmitting information from people as soon as they typed or auto-filled it into an online form. That way, the company would have it even if those people immediately changed their minds and closed the page.

This is important because it goes against what people expect:

In yesterday’s report on Acurian Health, University of Washington law professor Ryan Calo told Gizmodo that giving users a “send” or “submit” button, but then sending the entered information regardless of whether the button is pressed or not, clearly violates a user’s expectation of what will happen. Calo said it could violate a federal law against unfair and deceptive practices, as well as laws against deceptive trade practices in California and Massachusetts. A complaint on those grounds, Calo said, “would not be laughed out of court.”

This kind of thing is going to happen more and more, in all sorts of areas of our lives. The Internet of Things is the Internet of sensors, and the Internet of surveillance. We’ve long passed the point where ordinary people have any technical understanding of the different ways networked computers violate their privacy. Government needs to step in and regulate businesses down to reasonable practices. Which means government needs to prioritize security over their own surveillance needs.

Posted on June 29, 2017 at 6:51 AM • View Comments

Stealing Browsing History Using Your Phone's Ambient Light Sensor

There has been a flurry of research into using the various sensors on your phone to steal data in surprising ways. Here’s another: using the phone’s ambient light sensor to detect what’s on the screen. It’s a proof of concept, but the paper’s general conclusions are correct:

There is a lesson here that designing specifications and systems from a privacy engineering perspective is a complex process: decisions about exposing sensitive APIs to the web without any protections should not be taken lightly. One danger is that specification authors and browser vendors will base decisions on overly general principles and research results which don’t apply to a particular new feature (similarly to how protections on gyroscope readings might not be sufficient for light sensor data).

Posted on April 28, 2017 at 6:17 AM • View Comments

Acoustic Attack Against Accelerometers

Interesting acoustic attack against the MEMS accelerometers in devices like FitBits.

Millions of accelerometers reside inside smartphones, automobiles, medical devices, anti-theft devices, drones, IoT devices, and many other industrial and consumer applications. Our work investigates how analog acoustic injection attacks can damage the digital integrity of the capacitive MEMS accelerometer. Spoofing such sensors with intentional acoustic interference enables an out-of-spec pathway for attackers to deliver chosen digital values to microprocessors and embedded systems that blindly trust the unvalidated integrity of sensor outputs. Our contributions include (1) modeling the physics of malicious acoustic interference on MEMS accelerometers, (2) discovering the circuit-level security flaws that cause the vulnerabilities by measuring acoustic injection attacks on MEMS accelerometers as well as systems that employ on these sensors, and (3) two software-only defenses that mitigate many of the risks to the integrity of MEMS accelerometer outputs.

This is not that a big deal with things like FitBits, but as IoT devices get more autonomous—and start making decisions and then putting them into effect automatically—these vulnerabilities will become critical.

Academic paper.

Posted on April 4, 2017 at 6:23 AM • View Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.