Electric vehicles (EVs) in Vehicle-to-Grid (V2G) systems act as distributed energy resources that support grid stability. Centralized coordination such as the extended State Space Model (eSSM) enhances scalability and estimation efficiency but may introduce new cyber-attack surfaces. This paper presents a stealthy False Data Injection Attack (FDIA) targeting eSSM-based V2G coordination. Unlike prior studies that assume attackers can disrupt physical charging or discharging processes, we consider an adversary who compromises only a subset of EVs, and limiting their influence to the manipulation of reported State of Charge (SoC) and power measurements. By doing so, the attacker can deceive the operator's perception of fleet flexibility while remaining consistent with model-based expectations, thus evading anomaly detection. Numerical simulations show that the proposed stealthy FDIA can deteriorate grid frequency stability even without direct access to control infrastructure. These findings highlight the need for enhanced detection and mitigation mechanisms tailored to aggregated V2G frameworks

翻译：电动汽车在车辆到电网（V2G）系统中作为分布式能源资源，支持电网稳定性。集中式协同方法（如扩展状态空间模型（eSSM））提升了可扩展性和估计效率，但也可能引入新的网络攻击面。本文提出一种针对基于eSSM的V2G协同的隐蔽虚假数据注入攻击（FDIA）。与先前假设攻击者能够破坏物理充放电过程的研究不同，我们考虑一个仅破坏部分电动汽车、并将其影响限制在篡改上报的荷电状态（SoC）和功率测量值的对手。通过这种方式，攻击者能够欺骗操作者对车队灵活性的感知，同时保持与基于模型的预期一致，从而规避异常检测。数值仿真表明，所提出的隐蔽FDIA即使不直接访问控制基础设施，也能恶化电网频率稳定性。这些发现凸显了针对聚合V2G框架增强检测与缓解机制的必要性。