Decentralized Physical Infrastructure Networks (DePIN) have emerged as a promising paradigm, offering numerous benefits across various domains. For instance, DePIN allows to share (and monetize) excess resources, such as computing capacity and network bandwidth, enabling the provisioning of a wide range of services, including anonymous navigation, data acquisition, and computation, in exchange for cryptocurrency. The above examples are just the tip of the iceberg of the dematerialization, distribution, and democratization capabilities of the DePIN paradigm. However, in addition to their potential advantages, the decentralized nature of DePIN applications also introduces significant security and privacy concerns that must be carefully addressed. In this paper, we analyze the security and privacy implications of the DePIN infrastructure focusing on two domains: Network Services and Computation for AI-based Tasks. By examining the major active projects within each domain, we identify common security and privacy issues that require urgent attention from the community. Specifically, vulnerabilities related to the sharing of resources with unknown entities pose significant risks to the integrity and reliability of DePIN networks. In addition, concerns related to the handling of sensitive data, such as personal information and financial transactions, underscore the importance of robust security measures. Furthermore, inherited cybersecurity challenges from the underlying blockchain technology, including Sybil attacks and consensus vulnerabilities, exacerbate the security landscape of DePIN networks. To bridge this gap, we propose several directions for future research aimed at addressing security issues common to the DePIN paradigm.