PreMSat: Preventing Magnetic Saturation Attack on Hall Sensors
PreMSat: Preventing Magnetic Saturation Attack on Hall Sensors
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DOI：
10.46586/tches.v2022.i4.438-462
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发表时间：
2022-08
期刊：
影响因子：
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通讯作者：
Anomadarshi Barua;M. A. Faruque
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作者：
Anomadarshi Barua;M. A. Faruque
使用假磁场欺骗被动霍尔传感器可能会将虚假数据注入连接系统的下游。在过去的六年里，一些作品试图为不同的传感器提供针对故意欺骗的防御。然而，它们要么只对有源传感器起作用，要么对抗外部注入的不需要的弱信号（例如，EMI、声学、超声波等），其只能欺骗其线性区域中的传感器输出。然而，它们不能抵抗强磁欺骗攻击，该攻击可以将无源霍尔传感器输出驱动到其饱和区域。我们称之为饱和攻击。在饱和区域，输出变得平坦，无法获取任何信息，导致传感器受到拒绝服务攻击，我们的工作开始填补这一空白，提供一种名为PreMSat的防御方法来抵御对被动霍尔传感器的饱和攻击。PreMSat背后的核心思想是，它可以产生一个内部磁场，该磁场具有与攻击者注入的外部磁场相同的强度，但极性相反。因此，PreMSat产生的内部磁场可以抵消注入的外部磁场，同时防止：（i）传感器线性区域中的故意欺骗，以及（ii）饱和区域中的饱和攻击。PreMSat集成了一个低电阻磁路来收集注入的外部磁场，并利用一个微调的PID控制器来实时消除外部磁场。PreMSat能够以低成本（14美元）防止在0 Hz-30 kHz的频率范围内具有高达4200 A-t的强度的磁饱和攻击，而现有的工作不能防止任何强度的饱和攻击。此外，它还能抵抗来自任何类型的饱和攻击，例如恒定、正弦和脉动磁场。我们对来自四个不同制造商的十个不同行业使用的霍尔传感器进行了300多个实验，以证明PreMSat的有效性，并发现在每个测试用例中，攻击前后信号之间的相关系数都大于0.94。此外，我们创建了一个原型的PreMSat和评估其性能在一个实际的系统-并网太阳能逆变器。我们发现，PreMSat可以令人满意地防止饱和攻击的被动霍尔传感器在实时。
Spoofing a passive Hall sensor with fake magnetic fields can inject false data into the downstream of connected systems. Several works have tried to provide a defense against the intentional spoofing to different sensors over the last six years. However, they either only work on active sensors or against externally injected unwanted weak signals (e.g., EMIs, acoustics, ultrasound, etc.), which can only spoof sensor output in its linear region. However, they do not work against a strong magnetic spoofing attack that can drive the passive Hall sensor output in its saturation region. We name this as the saturation attack. In the saturation region, the output gets flattened, and no information can be retrieved, resulting in a denial-of-service attack on the sensor.Our work begins to fill this gap by providing a defense named PreMSat against the saturation attack on passive Hall sensors. The core idea behind PreMSat is that it cangenerate an internal magnetic field having the same strength but in opposite polarity to external magnetic fields injected by an attacker. Therefore, the generated internal magnetic field by PreMSat can nullify the injected external field while preventing: (i) intentional spoofing in the sensor’s linear region, and (ii) saturation attack in the saturation region. PreMSat integrates a low-resistance magnetic path to collect the injected external magnetic fields and utilizes a finely tuned PID controller to nullify the external fields in real-time. PreMSat can prevent the magnetic saturation attack having a strength up to ∼4200 A-t within a frequency range of 0 Hz–30 kHz with low cost (∼$14), whereas the existing works cannot prevent saturation attacks with any strength. Moreover, it works against saturation attacks originating from any type, such as constant, sinusoidal, and pulsating magnetic fields. We did over 300 experiments on ten different industry-used Hall sensors from four different manufacturers to prove the efficacy of PreMSat and found that the correlation coefficient between the signals before the attack and after the attack is greater than 0.94 in every test case. Moreover, we create a prototype of PreMSat and evaluate its performance in a practical system — a grid-tied solar inverter. We find that PreMSat can satisfactorily prevent the saturation attack on passive Hall sensors in real-time.