The Internet of Things (IoT) is increasingly influencing and transforming various aspects of our daily lives. Contrary to popular belief, it raises security and privacy issues as it is used to collect data from consumers or automated systems. Numerous articles are published that discuss issues like centralised control systems and potential alternatives like integration with blockchain. Although a few recent surveys focused on the challenges and solutions facing the IoT ecosystem, most of them did not concentrate on the threats, difficulties, or blockchain-based solutions. Additionally, none of them focused on blockchain and IoT integration challenges and attacks. In the context of the IoT ecosystem, overall security measures are very important to understand the overall challenges. This article summarises difficulties that have been outlined in numerous recent articles and articulates various attacks and security challenges in a variety of approaches, including blockchain-based solutions and so on. More clearly, this contribution consolidates threats, access control issues, and remedies in brief. In addition, this research has listed some attacks on public blockchain protocols with some real-life examples that can guide researchers in taking preventive measures for IoT use cases. Finally, a future research direction concludes the research gaps by analysing contemporary research contributions.

翻译：物联网正日益影响并改变我们日常生活的方方面面。与普遍认知相反，由于物联网被用于收集消费者或自动化系统的数据，其引发了安全与隐私问题。已有大量文献探讨了集中式控制系统等问题，以及区块链集成等潜在替代方案。尽管近期少数综述聚焦于物联网生态系统面临的挑战与解决方案，但多数未着重分析威胁、困难或基于区块链的解决方案。此外，尚无研究专门关注区块链与物联网集成中的挑战与攻击。在物联网生态系统的背景下，全面理解整体安全措施至关重要。本文总结了近期多篇文献中概述的困难，并从多种方法（包括基于区块链的解决方案等）角度阐述了各类攻击与安全挑战。更明确而言，本贡献简要整合了威胁、访问控制问题及其应对措施。此外，本研究列举了公共区块链协议上的一些攻击实例及现实案例，可为研究人员在物联网应用场景中采取预防措施提供指导。最后，通过分析当代研究贡献，未来研究方向揭示了研究空白。