What Type of Mobile Attack Uses Loudspeaker Data to Breach Speech Privacy?

312-50v12 By islever Editorial Last updated

Hacking Mobile Platforms

Short answer

C A Spearphone attack exploits the phone's loudspeaker output, using a malicious app to capture speech privacy data such as voice assistant and audio playback.

Question

Kate dropped her phone and subsequently encountered an issue with the phone's internal speaker. Thus, she is using the phone's loudspeaker for phone calls and other activities. Bob, an attacker, takes advantage of this vulnerability and secretly exploits the hardware of Kate's phone so that he can monitor the loudspeaker's output from data sources such as voice assistants, multimedia messages, and audio files by using a malicious app to breach speech privacy. What is the type of attack Bob performed on Kate in the above scenario?
  1. SIM card attack
  2. aLTEr attack
  3. Spearphone attack Correct Answer
  4. Man-in-the-disk attack

Key Takeaways

The exam tests whether you can distinguish an on-device loudspeaker side-channel attack from cellular-network and storage attacks; the trap is choosing aLTEr simply because it sounds like a mobile attack.

Spearphone is a mobile side-channel attack in which a malicious Android app captures loudspeaker output to infer speech and media content. This page explains why the scenario describes a Spearphone attack and rules out SIM-card, aLTEr, and man-in-the-disk alternatives.

Common mistake: Many learners pick aLTEr because it is a well-known mobile-network attack, but aLTEr targets LTE traffic redirection, not loudspeaker output captured by a malicious app on Kate's phone.

Expert Analysis

Why the Answer Is Correct

Spearphone is a side-channel attack in which an unprivileged Android app samples accelerometer data to recover reverberations from the loudspeaker, allowing an attacker to monitor voice assistants, audio files, and multimedia messages without microphone permission. The scenario explicitly says Kate uses the loudspeaker for calls and other activities, and Bob exploits the phone hardware through a malicious app to breach speech privacy, which matches the Spearphone threat model precisely. As shaody noted, "A spearphone attack allows Android apps to record loudspeaker data without any privileges." The defining elements are the malicious on-device app and the loudspeaker-derived speech data, not cellular signaling or SIM functionality. Therefore option C is the only choice that aligns with the described vulnerability and attack outcome.

Why the Other Options Are Wrong

A SIM card attack targets the SIM, SIM Toolkit, or over-the-air provisioning channel and does not capture loudspeaker output or speech reverberations. An aLTEr attack is an LTE network attack that manipulates GTP traffic to redirect DNS and perform interception at the carrier level, which has nothing to do with a malicious app monitoring Kate's phone speaker. A man-in-the-disk attack abuses shared external storage so one app can read or tamper with another app's files, not eavesdrop on audio played through the loudspeaker. None of these options involves the accelerometer-sensed loudspeaker side channel that makes Spearphone unique.

Community Comment Notes

Multiple commenters converge on the same answer: insaniunt simply states "C. Spearphone attack", while LordXander and dobarb both point to CEHv12 page 2649 as the source. shaody adds the useful technical detail that Android apps can record loudspeaker data without privileges, which matches the exam's emphasis on an unprivileged malicious app. The unanimous vote record is consistent, but the decisive evidence is the technical match to Spearphone and the CEH mobile hacking objective, not the vote count alone.

Exam Strategy

When a mobile question mentions a malicious app capturing loudspeaker output without microphone permission, lock onto Spearphone immediately. Eliminate network-level options such as aLTEr and SIM card attacks because they target cellular infrastructure, not on-device audio side channels.

Frequently Asked Questions

Why is an aLTEr attack not correct for Kate's loudspeaker privacy breach?

aLTEr is a 4G/LTE network redirection attack targeting DNS traffic, not an on-device malicious app capturing loudspeaker output.

Why is man-in-the-disk wrong in this Spearphone scenario?

Man-in-the-disk abuses shared external storage between apps; it does not monitor loudspeaker reverberations or speech privacy data.

More 312-50v12 FAQ →

Community Votes

C
100%

100% of anonymous learners picked answer C. Votes are pick records left by other test-takers — they are not the verified answer.

Discussion 4 contributions

Compiled from public community threads and reader submissions, lightly edited for clarity. Handles and vote tallies are shown as recorded, and comments reflect the views of individual contributors.

From public community threads 4

  1. shaody 👍 1 Answered C
    A spearphone attack allows Android apps to record loudspeaker data without any privileges.
  2. insaniunt 👍 2 Answered C
    C. Spearphone attack
  3. dobarb 👍 1
    C. CEH page 2649
  4. LordXander 👍 1 Answered C
    CEHv12 2649

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