Voice assistants (VA) have become prevalent on a wide range of personal devices such as smartphones and smart speakers. As companies build voice assistants with extra functionalities, attacks that trick a voice assistant into performing malicious behaviors can pose a significant threat to a user’s security, privacy, and even safety. However, the diverse attacks and stand-alone defenses in the literature often lack a systematic perspective, making it challenging for designers to properly identify, understand, and mitigate the security threats against voice assistants. To overcome this problem, this article provides a thorough survey of the attacks and countermeasures for voice assistants. We systematize a broad category of relevant but seemingly unrelated attacks by the vulnerable system components and attack methods, and categorize existing countermeasures based on the defensive strategies from a system designer’s perspective. To assist designers in planning defense based on their demands, we provide a qualitative comparison of existing countermeasures by the implementation cost, usability, and security and propose practical suggestions. We envision this work can help build more reliability into voice assistants and promote research in this fast-evolving area.

语音助手 (VA) 已在智能手机和智能扬声器等各种个人设备上普及。随着公司构建具有额外功能的语音助手，诱骗语音助手执行恶意行为的攻击可能对用户的安全、隐私甚至人身安全构成重大威胁。然而，文献中多样化的攻击和独立的防御往往缺乏系统的视角，这使得设计人员很难正确识别、理解和减轻针对语音助手的安全威胁。为了克服这个问题，本文对语音助手的攻击和对策进行了全面的调查。我们通过易受攻击的系统组件和攻击方法将一大类相关但看似无关的攻击系统化，从系统设计者的角度，根据防御策略对现有的对策进行分类。为了帮助设计者根据他们的需求规划防御，我们从实施成本、可用性和安全性方面对现有对策进行定性比较，并提出实用建议。我们设想这项工作可以帮助提高语音助手的可靠性，并促进这一快速发展领域的研究。