Cloud-Assisted IoT-Based SCADA Systems Security: A Review of the State of the Art and Future Challenges <s> IV. RECOMMENDATIONS AND BEST PRACTICES FOR SECURING IoT-CLOUD BASED SCADA SYSTEMS <s> Supervisory Control and Data Acquisition(SCADA) systems are deeply ingrained in the fabric of critical infrastructure sectors. These computerized real-time process control systems, over geographically dispersed continuous distribution operations, are increasingly subject to serious damage and disruption by cyber means due to their standardization and connectivity to other networks. However, SCADA systems generally have little protection from the escalating cyber threats. In order to understand the potential danger and to protect SCADA systems, in this paper, we highlight their difference from standard IT systems and present a set of security property goals. Furthermore, we focus on systematically identifying and classifying likely cyber attacks including cyber-induced cyber-physical attack son SCADA systems. Determined by the impact on control performance of SCADA systems, the attack categorization criteria highlights commonalities and important features of such attacks that define unique challenges posed to securing SCADA systems versus traditional Information Technology(IT) systems. <s> BIB001 </s> Cloud-Assisted IoT-Based SCADA Systems Security: A Review of the State of the Art and Future Challenges <s> IV. RECOMMENDATIONS AND BEST PRACTICES FOR SECURING IoT-CLOUD BASED SCADA SYSTEMS <s> This document provides guidance on how to secure Industrial Control Systems (ICS), including Supervisory Control and Data Acquisition (SCADA) systems, Distributed Control Systems (DCS), and other control system configurations such as Programmable Logic Controllers (PLC), while addressing their unique performance, reliability, and safety requirements. The document provides an overview of ICS and typical system topologies, identifies typical threats and vulnerabilities to these systems, and provides recommended security countermeasures to mitigate the associated risks. <s> BIB002
SCADA systems in IoT-cloud environment are not like regular IT systems; we cannot assume that by simply using some strong password policies, updated antivirus protection, firewalls, or frequent patching will solve the problems (as they would for simpler IT systems). Therefore, countermeasures are required that directly address the security needs of SCADA systems in IoT-cloud environments. Recently, the Internet Engineering Task Force (IETF) has been working on a new draft that focuses on security considerations for Industrial IoT (IIoT) in IP-based environments. This draft standard also provides an overview on the present state of the art (as of 2013) and emphasizes that future connections are moving towards an all-IP solution. The current draft standard defines five security profiles: IoT devices for home use, IoT devices with no security requirements, IoT devices for industrial usage, IoT devices for managed home use, and IoT devices for advanced industrial usage. When considering the future for secure and flexible industrial IoT networks, this draft identifies that Datagram Transport Layer Security (DTLS) will form the basic building block for these systems. However, the draft argues that there is a need to introduce more interconnectivity among the multiple layers of security in the IoT and cloud based industrial systems. Similarly, the methodology named ''Prevention, Protection and REaction to CYber attackS to critical infrastructurEs'' (PRECYSE) is a security methodology intended to improve by design the reliability, resilience and security of Information and Communication Technology (ICT) that supports CI's such as CPS, SCADA, IIoT, and so on. PRECYSE is built on research standards already in existence and has a special focus on relevant security, policy, privacy, ethical and legal issues for CIs. The major goals of PRECYSE for CIs such as SCADA systems  are as follows: -Investigating privacy and ethical issues. -Improving resilience through a security architecture. -Providing tools for preventing and protecting against cyberattacks on SCADA systems and controlling the reaction to such attacks. -Presenting a methodology for identifying assets and their associated vulnerabilities and threats. -Deploying prototypes at two sites, one in the transport sector and the other in the energy sector. Some basic principles can be considered for protecting Industrial IoT and IIoT-cloud based SCADA systems, as shown in Fig. 5 . These principles have the objective of protecting vulnerable infrastructure by surrounding these systems with a combination of security tools based on currently available good practices. Following is a brief overview of few such good practices that helps in improving the security of IoT and cloud based SCADA systems, keeping in view the guidelines of NIST SP 800-53 BIB001 , NIST SP 800-53, Revision 4  , NIST SP 800-82, Revision 2 BIB002 , and other literature reviewed in the reference section. 