The Internet of Things (IoT) refers to a network of physical objects that have been equipped with software, sensors and communication technologies. These objects are capable of exchanging data with other devices through the Internet. The concept of the IoT is to enhance daily routines through the automation or reduction of human intervention in task completion. The widespread adoption of the IoT has resulted in a significant increase in the occurrence of malicious attacks, leading to substantial losses. This paper provides a concise overview of the security concerns present in the IoT ecosystem. It discusses multiple types of attacks that occur in the IoT environment and then delves into layer-specific malicious attacks. Additionally, we highlight the methodologies employed to mitigate attacks inside the IoT ecosystem.