The rapid growth of small Unmanned Aerial Systems (sUAS) for civil and commercial missions has intensified concerns about their resilience to cyber-security threats. Operating within the emerging UAS Traffic Management (UTM) framework, these lightweight and highly networked platforms depend on secure communication, navigation, and surveillance (CNS) subsystems that are vulnerable to spoofing, jamming, hijacking, and data manipulation. While prior reviews of UAS security addressed these challenges at a conceptual level, a detailed, system-oriented analysis for resource-constrained sUAS remains lacking. This paper presents a comprehensive survey of cyber-security vulnerabilities and defenses tailored to the sUAS and UTM ecosystem. We organize existing research across the full cyber-physical stack, encompassing CNS, data links, sensing and perception, UTM cloud access, and software integrity layers, and classify attack vectors according to their technical targets and operational impacts. Correspondingly, we review defense mechanisms ranging from classical encryption and authentication to adaptive intrusion detection, lightweight cryptography, and secure firmware management. By mapping threats to mitigation strategies and evaluating their scalability and practical effectiveness, this work establishes a unified taxonomy and identifies open challenges for achieving safe, secure, and scalable sUAS operations within future UTM environments.

翻译：民用和商业任务中小型无人机系统的快速增长加剧了对其网络安全威胁抵御能力的担忧。这些轻量级、高度网络化的平台在新兴的无人机交通管理框架内运行，依赖于易受欺骗、干扰、劫持和数据操纵的安全通信、导航与监视子系统。尽管先前关于无人机安全的综述在概念层面探讨了这些挑战，但针对资源受限的小型无人机系统仍缺乏详细的、面向系统的分析。本文对面向小型无人机系统与无人机交通管理生态系统的网络安全漏洞及防御措施进行了全面综述。我们按网络物理全栈组织现有研究，涵盖通信导航监视、数据链路、感知与认知、无人机交通管理云接入及软件完整性等层级，并根据攻击媒介的技术目标和操作影响进行分类。相应地，我们综述了从经典加密认证到自适应入侵检测、轻量级密码学及安全固件管理等防御机制。通过将威胁映射至缓解策略并评估其可扩展性与实际有效性，本研究建立了统一分类体系，并指出了在未来无人机交通管理环境中实现安全可靠、可扩展的小型无人机系统运行所面临的开放挑战。