The people-centric Internet of Things, as an essential part of the general IoT ecosystem, relies heavily on intelligent wearables to control and actuate the ambient/remote “things” according to the sensed information or collected instruction from the specific person. Intelligent wearables, although becoming increasingly prevalent and pervasive, are vulnerable to various cyber-attacks due to their intrinsic characteristics, which consequently brings up unprecedented security challenges in terms of privacy leakage, financial loss, and even malicious invasion of other connected IoT components and applications. Therefore, it is of great necessity to keep intelligent wearables reliable and trustworthy before being able to secure the core parts of IoT. Toward this end, we provide in this article a survey of available attack methodologies on intelligent wearables as well as the corresponding countermeasures, from the perspectives of data integrity, authenticity, and privacy.