Selected aspects of security mechanisms for cloud computing – current solutions and development perspectives

The security aspects of cloud computing, especially the security of data, become more and more important. It is necessary to find and develop the new mechanisms to secure the cloud. The problem presented in the paper concerns the mechanisms for security of cloud computing with special attention paid to aspects of access control in clouds – the state of the art and the perspectives for the future

FaaS: Federation-as-a-Service

This document is the main high-level architecture specification of the SUNFISH cloud federation solution. Its main objective is to introduce the concept of Federation-as-a-Service (FaaS) and the SUNFISH platform. FaaS is the new and innovative cloud federation service proposed by the SUNFISH project. The document defines the functionalities of FaaS, its governance and precise objectives. With respect to these objectives, the document proposes the high-level architecture of the SUNFISH platform: the software architecture that permits realising a FaaS federation. More specifically, the document describes all the components forming the platform, the offered functionalities and their high-level interactions underlying the main FaaS functionalities. The document concludes by outlining the main implementation strategies towards the actual implementation of the proposed cloud federation solution.Comment: Technical Report Edited by Francesco Paolo Schiavo, Vladimiro Sassone, Luca Nicoletti and Andrea Margher

Towards Practical Access Control and Usage Control on the Cloud using Trusted Hardware

Cloud-based platforms have become the principle way to store, share, and synchronize files online. For individuals and organizations alike, cloud storage not only provides resource scalability and on-demand access at a low cost, but also eliminates the necessity of provisioning and maintaining complex hardware installations. Unfortunately, because cloud-based platforms are frequent victims of data breaches and unauthorized disclosures, data protection obliges both access control and usage control to manage user authorization and regulate future data use. Encryption can ensure data security against unauthorized parties, but complicates file sharing which now requires distributing keys to authorized users, and a mechanism that prevents revoked users from accessing or modifying sensitive content. Further, as user data is stored and processed on remote ma- chines, usage control in a distributed setting requires incorporating the local environmental context at policy evaluation, as well as tamper-proof and non-bypassable enforcement. Existing cryptographic solutions either require server-side coordination, offer limited flexibility in data sharing, or incur significant re-encryption overheads on user revocation. This combination of issues are ill-suited within large-scale distributed environments where there are a large number of users, dynamic changes in user membership and access privileges, and resources are shared across organizational domains. Thus, developing a robust security and privacy solution for the cloud requires: fine-grained access control to associate the largest set of users and resources with variable granularity, scalable administration costs when managing policies and access rights, and cross-domain policy enforcement. To address the above challenges, this dissertation proposes a practical security solution that relies solely on commodity trusted hardware to ensure confidentiality and integrity throughout the data lifecycle. The aim is to maintain complete user ownership against external hackers and malicious service providers, without losing the scalability or availability benefits of cloud storage. Furthermore, we develop a principled approach that is: (i) portable across storage platforms without requiring any server-side support or modifications, (ii) flexible in allowing users to selectively share their data using fine-grained access control, and (iii) performant by imposing modest overheads on standard user workloads. Essentially, our system must be client-side, provide end-to-end data protection and secure sharing, without significant degradation in performance or user experience. We introduce NeXUS, a privacy-preserving filesystem that enables cryptographic protection and secure file sharing on existing network-based storage services. NeXUS protects the confidentiality and integrity of file content, as well as file and directory names, while mitigating against rollback attacks of the filesystem hierarchy. We also introduce Joplin, a secure access control and usage control system that provides practical attribute-based sharing with decentralized policy administration, including efficient revocation, multi-domain policies, secure user delegation, and mandatory audit logging. Both systems leverage trusted hardware to prevent the leakage of sensitive material such as encryption keys and access control policies; they are completely client-side, easy to install and use, and can be readily deployed across remote storage platforms without requiring any server-side changes or trusted intermediary. We developed prototypes for NeXUS and Joplin, and evaluated their respective overheads in isolation and within a real-world environment. Results show that both prototypes introduce modest overheads on interactive workloads, and achieve portability across storage platforms, including Dropbox and AFS. Together, NeXUS and Joplin demonstrate that a client-side solution employing trusted hardware such as Intel SGX can effectively protect remotely stored data on existing file sharing services

Designing the Extended Zero Trust Maturity Model A Holistic Approach to Assessing and Improving an Organization’s Maturity Within the Technology, Processes and People Domains of Information Security

Zero Trust is an approach to security where implicit trust is removed, forcing applications, workloads, servers and users to verify themselves every time a request is made. Furthermore, Zero Trust means assuming anything can be compromised, and designing networks, identities and systems with this in mind and following the principle of least privilege. This approach to information security has been coined as the solution to the weaknesses of traditional perimeter-based information security models, and adoption is starting to increase. However, the principles of Zero Trust are only applied within the technical domain to aspects such as networks, data and identities in past research. This indicates a knowledge gap, as the principles of Zero Trust could be applied to organizational domains such as people and processes to further strengthen information security, resulting in a holistic approach. To fill this gap, we employed design science research to develop a holistic maturity model for Zero Trust maturity based on these principles: The EZTMM. We performed two systematic literature reviews on Zero Trust and Maturity Model theory respectively and collaborated closely with experts and practitioners on the operational, tactical and strategic levels of six different organizations. The resulting maturity model was anchored in prior Zero Trust and maturity model literature, as well as practitioner and expert experiences and knowledge. The EZTMM was evaluated by our respondent organizations through two rounds of interviews before being used by one respondent organization to perform a maturity assessment of their own organization as a part of our case study evaluation. Each interview round resulted in ample feedback and learning, while the case study allowed us to evaluate and improve on the model in a real-world setting. Our contribution is twofold: A fully functional, holistic Zero Trust maturity model with an accompanying maturity assessment spreadsheet (the artifact), and our reflections and suggestions regarding further development of the EZTMM and research on the holistic application of Zero Trust principles for improved information security

Designing the Extended Zero Trust Maturity Model A Holistic Approach to Assessing and Improving an Organization’s Maturity Within the Technology, Processes and People Domains of Information Security

Zero Trust is an approach to security where implicit trust is removed, forcing applications, workloads, servers and users to verify themselves every time a request is made. Furthermore, Zero Trust means assuming anything can be compromised, and designing networks, identities and systems with this in mind and following the principle of least privilege. This approach to information security has been coined as the solution to the weaknesses of traditional perimeter-based information security models, and adoption is starting to increase. However, the principles of Zero Trust are only applied within the technical domain to aspects such as networks, data and identities in past research. This indicates a knowledge gap, as the principles of Zero Trust could be applied to organizational domains such as people and processes to further strengthen information security, resulting in a holistic approach. To fill this gap, we employed design science research to develop a holistic maturity model for Zero Trust maturity based on these principles: The EZTMM. We performed two systematic literature reviews on Zero Trust and Maturity Model theory respectively and collaborated closely with experts and practitioners on the operational, tactical and strategic levels of six different organizations. The resulting maturity model was anchored in prior Zero Trust and maturity model literature, as well as practitioner and expert experiences and knowledge. The EZTMM was evaluated by our respondent organizations through two rounds of interviews before being used by one respondent organization to perform a maturity assessment of their own organization as a part of our case study evaluation. Each interview round resulted in ample feedback and learning, while the case study allowed us to evaluate and improve on the model in a real-world setting. Our contribution is twofold: A fully functional, holistic Zero Trust maturity model with an accompanying maturity assessment spreadsheet (the artifact), and our reflections and suggestions regarding further development of the EZTMM and research on the holistic application of Zero Trust principles for improved information security

Identity management in a public IaaS Cloud

In this thesis the unique environment that is the public IaaS cloud along with its differences from a traditional data center environment has been considered. The Cloud Security Alliance (CSA), states that “Managing identities and access control for enterprise applications remains one of the greatest challenges facing IT today”. The CSA also points out that “there is a lack of consistent secure methods for extending identity management into the cloud and across the cloud” [1]. This thesis examines this challenge of managing identities in the cloud by developing a list of best practices for implementing identity management in the cloud. These best practices were then tested by simulated misuse cases which were tested in a prototype of the implementation strategy. The results and analysis of the misuse cases show that the implementation of the identity management solution solves the problem of managing identities for the control of the infrastructure in the cloud. However, the analysis also shows that there are still areas where the properly implemented identity management solution fails to mitigate attacks to the infrastructure. These failures in particular are attacks that are sourced from the subscriber environments in the cloud. Finally, the best practices from this thesis also present some consistent methods for extending identity management into the cloud

Towards Identity Relationship Management For Internet of Things

Identity and Access Management (IAM) is in the core of any information systems. Traditional IAM systems manage users, applications, and devices within organizational boundaries, and utilize static intelligence for authentication and access control. Identity federation has helped a lot to deal with boundary limitation, but still limited to static intelligence – users, applications and devices must be under known boundaries. However, today’s IAM requirements are much more complex. Boundaries between enterprise and consumer space, on premises and cloud, personal devices and organization owned devices, and home, work and public places are fading away. These challenges get more complicated for Internet of Things (IoTs) due to their diverse use and portability nature. IoTs are being used in consumer space, healthcare, manufacturing, retails, entertainment, transportation, public sector, and many other places. Identity Relationship Management (IRM) can help in solving some of these challenges as it uses a more natural way of access management - a relationship-based access control methodology. IRM can perform identity and relationship management beyond home and organizational boundaries and can simplify authorization and authentication using dynamic intelligence based on relationship. In this research, we studied the needs of IRM for the Internet of Things. We explored four fundamental questions in IRM: what relationships need to be supported in IRM, how relationships can be supported in IRM, how relationship can be used for access control, and finally what infrastructure is required to support IRM. Since relationship is globally spread out and perimeter-less in nature, we designed the IRM service with a global scalable, modular, and borderless architecture. Instead of building something from scratch, we slightly modified the UMA 2.0 protocol built on top of OAuth 2.0 to make the relationship-based access control feature easily pluggable with existing IAM frameworks. We implemented a proof-of-concept to demonstrate and analyze the results of this research. This dissertation serves as the foundation for future research and development in IRM domain

Contributions to the privacy provisioning for federated identity management platforms

Identity information, personal data and user’s profiles are key assets for organizations and companies by becoming the use of identity management (IdM) infrastructures a prerequisite for most companies, since IdM systems allow them to perform their business transactions by sharing information and customizing services for several purposes in more efficient and effective ways. Due to the importance of the identity management paradigm, a lot of work has been done so far resulting in a set of standards and specifications. According to them, under the umbrella of the IdM paradigm a person’s digital identity can be shared, linked and reused across different domains by allowing users simple session management, etc. In this way, users’ information is widely collected and distributed to offer new added value services and to enhance availability. Whereas these new services have a positive impact on users’ life, they also bring privacy problems. To manage users’ personal data, while protecting their privacy, IdM systems are the ideal target where to deploy privacy solutions, since they handle users’ attribute exchange. Nevertheless, current IdM models and specifications do not sufficiently address comprehensive privacy mechanisms or guidelines, which enable users to better control over the use, divulging and revocation of their online identities. These are essential aspects, specially in sensitive environments where incorrect and unsecured management of user’s data may lead to attacks, privacy breaches, identity misuse or frauds. Nowadays there are several approaches to IdM that have benefits and shortcomings, from the privacy perspective. In this thesis, the main goal is contributing to the privacy provisioning for federated identity management platforms. And for this purpose, we propose a generic architecture that extends current federation IdM systems. We have mainly focused our contributions on health care environments, given their particularly sensitive nature. The two main pillars of the proposed architecture, are the introduction of a selective privacy-enhanced user profile management model and flexibility in revocation consent by incorporating an event-based hybrid IdM approach, which enables to replace time constraints and explicit revocation by activating and deactivating authorization rights according to events. The combination of both models enables to deal with both online and offline scenarios, as well as to empower the user role, by letting her to bring together identity information from different sources. Regarding user’s consent revocation, we propose an implicit revocation consent mechanism based on events, that empowers a new concept, the sleepyhead credentials, which is issued only once and would be used any time. Moreover, we integrate this concept in IdM systems supporting a delegation protocol and we contribute with the definition of mathematical model to determine event arrivals to the IdM system and how they are managed to the corresponding entities, as well as its integration with the most widely deployed specification, i.e., Security Assertion Markup Language (SAML). In regard to user profile management, we define a privacy-awareness user profile management model to provide efficient selective information disclosure. With this contribution a service provider would be able to accesses the specific personal information without being able to inspect any other details and keeping user control of her data by controlling who can access. The structure that we consider for the user profile storage is based on extensions of Merkle trees allowing for hash combining that would minimize the need of individual verification of elements along a path. An algorithm for sorting the tree as we envision frequently accessed attributes to be closer to the root (minimizing the access’ time) is also provided. Formal validation of the above mentioned ideas has been carried out through simulations and the development of prototypes. Besides, dissemination activities were performed in projects, journals and conferences.Programa Oficial de Doctorado en Ingeniería TelemáticaPresidente: María Celeste Campo Vázquez.- Secretario: María Francisca Hinarejos Campos.- Vocal: Óscar Esparza Martí

Access Control Within MQTT-based IoT environments

IoT applications, which allow devices, companies, and users to join the IoT ecosystems, are growing in popularity since they increase our lifestyle quality day by day. However, due to the personal nature of the managed data, numerous IoT applications represent a potential threat to user privacy and data confidentiality. Insufficient security protection mechanisms in IoT applications can cause unauthorized users to access data. To solve this security issue, the access control systems, which guarantee only authorized entities to access the resources, are proposed in academic and industrial environments. The main purpose of access control systems is to determine who can access specific resources under which circumstances via the access control policies. An access control model encapsulates the defined set of access control policies. Access control models have been proposed also for IoT environments to protect resources from unauthorized users. Among the existing solutions, the proposals which are based on Attribute-Based Access Control (ABAC) model, have been widely adopted in the last years. In the ABAC model, authorizations are determined by evaluating attributes associated with the subject, object, and environmental properties. ABAC model provides outstanding flexibility and supports fine-grained, context-based access control policies. These characteristics perfectly fit the IoT environments. In this thesis, we employ ABAC to regulate the reception and the publishing of messages exchanged within MQTT-based IoT environments. MQTT is a standard application layer protocol that enables the communication of IoT devices. Even though the current access control systems tailored for IoT environments in the literature handle data sharing among the IoT devices by employing various access control models and mechanisms to address the challenges that have been faced in IoT environments, surprisingly two research challenges have still not been sufficiently examined. The first challenge that we want to address in this thesis is to regulate data sharing among interconnected IoT environments. In interconnected IoT environments, data exchange is carried out by devices connected to different environments. The majority of proposed access control frameworks in the literature aimed at regulating the access to data generated and exchanged within a single IoT environment by adopting centralized enforcement mechanisms. However, currently, most of the IoT applications rely on IoT devices and services distributed in multiple IoT environments to satisfy users’ demands and improve their functionalities. The second challenge that we want to address in this thesis is to regulate data sharing within an IoT environment under ordinary and emergency situations. Recent emergencies, such as the COVID-19 pandemic, have shown that proper emergency management should provide data sharing during an emergency situation to monitor and possibly mitigate the effect of the emergency situation. IoT technologies provide valid support to the development of efficient data sharing and analysis services and appear well suited for building emergency management applications. Additionally, IoT has magnified the possibility of acquiring data from different sensors and employing these data to detect and manage emergencies. An emergency management application in an IoT environment should be complemented with a proper access control approach to control data sharing against unauthorized access. In this thesis, we do a step to address two open research challenges related to data protection in IoT environments which are briefly introduced above. To address these challenges, we propose two access control frameworks rely on ABAC model: the first one regulates data sharing among interconnected MQTT-based IoT environments, whereas the second one regulates data sharing within MQTT-based IoT environment during ordinary and emergency situations.IoT applications, which allow devices, companies, and users to join the IoT ecosystems, are growing in popularity since they increase our lifestyle quality day by day. However, due to the personal nature of the managed data, numerous IoT applications represent a potential threat to user privacy and data confidentiality. Insufficient security protection mechanisms in IoT applications can cause unauthorized users to access data. To solve this security issue, the access control systems, which guarantee only authorized entities to access the resources, are proposed in academic and industrial environments. The main purpose of access control systems is to determine who can access specific resources under which circumstances via the access control policies. An access control model encapsulates the defined set of access control policies. Access control models have been proposed also for IoT environments to protect resources from unauthorized users. Among the existing solutions, the proposals which are based on Attribute-Based Access Control (ABAC) model, have been widely adopted in the last years. In the ABAC model, authorizations are determined by evaluating attributes associated with the subject, object, and environmental properties. ABAC model provides outstanding flexibility and supports fine-grained, context-based access control policies. These characteristics perfectly fit the IoT environments. In this thesis, we employ ABAC to regulate the reception and the publishing of messages exchanged within MQTT-based IoT environments. MQTT is a standard application layer protocol that enables the communication of IoT devices. Even though the current access control systems tailored for IoT environments in the literature handle data sharing among the IoT devices by employing various access control models and mechanisms to address the challenges that have been faced in IoT environments, surprisingly two research challenges have still not been sufficiently examined. The first challenge that we want to address in this thesis is to regulate data sharing among interconnected IoT environments. In interconnected IoT environments, data exchange is carried out by devices connected to different environments. The majority of proposed access control frameworks in the literature aimed at regulating the access to data generated and exchanged within a single IoT environment by adopting centralized enforcement mechanisms. However, currently, most of the IoT applications rely on IoT devices and services distributed in multiple IoT environments to satisfy users’ demands and improve their functionalities. The second challenge that we want to address in this thesis is to regulate data sharing within an IoT environment under ordinary and emergency situations. Recent emergencies, such as the COVID-19 pandemic, have shown that proper emergency management should provide data sharing during an emergency situation to monitor and possibly mitigate the effect of the emergency situation. IoT technologies provide valid support to the development of efficient data sharing and analysis services and appear well suited for building emergency management applications. Additionally, IoT has magnified the possibility of acquiring data from different sensors and employing these data to detect and manage emergencies. An emergency management application in an IoT environment should be complemented with a proper access control approach to control data sharing against unauthorized access. In this thesis, we do a step to address two open research challenges related to data protection in IoT environments which are briefly introduced above. To address these challenges, we propose two access control frameworks rely on ABAC model: the first one regulates data sharing among interconnected MQTT-based IoT environments, whereas the second one regulates data sharing within MQTT-based IoT environment during ordinary and emergency situations