IoT or The Internet of Things is the latest modern-day technology that is currently transforming the society in which we live in. Various opportunities in IoT have increased the demand for the need of IoT enabled technologies to a great extent. Bluetooth Low Energy (BLE) is one such technology which helped advance the scope of IoT enabled technologies in smart cities and various other corporate organizations. Asset tracking, person location tracking are some of the key use cases of the BLE technology. Hence integration of BLE technology has helped IoT to reach its technological advancement to a next level. With the advancements in technology, many researches in services like indoor localization had been carried out. Indoor localization is that ability of technology to actually find the exact location of a person or device existing in an indoor setting. So this technology feature have been accepted and put into use in sectors like industries, building management, health sectors and so on. Hence this technology is now integrated into latest smart cities so as to maximize the utilization of the technology to the fullest. Security is one major concern with the emergence of a technology. Many algorithms or protocols help to curb the security threats on a major scale. In this paper we had also discuss on some security issues faced in IoT system to know how effectively and carefully one should implement and design an IoT system to ensure that there are no security flaws. This paper focuses on applications of IoT and BLE technologies with some of its security threats like Denial of Service (DoS) attacks with a proposal for improvement in boarding passes issued to passengers in airports that enable passenger tracking possible in airports around the world. Section I consists of the introduction which describes the brief idea on the paper followed by Section II which is the literature review which consists of applications, security and other various aspects of IoT and BLE systems. Section III is a proposal for improved boarding pass system and in the end is Section IV which concludes the paper with a detailed conclusion.