Policy Management in Cloud

Cloud computing offers cost effective services on-demand which encourage critical infrastructure providers to consider migrating to the cloud. Critical infrastructures are considered as a backbone of modern societies such as power plants and water. Information in cloud computing is likely to be shared among different entities, which could have various degrees of sensitivity. This requires robust isolation and access control mechanisms. Although various access control models and policies have been developed, they cannot fulfil requirements for a cloud based access control system. The reason is that cloud computing has a diverse sets of security requirements and unique security challenges such as multi-tenant and heterogeneity of security policies, rules and domains. This thesis provides a detailed study of cloud computing security challenges and threats, which were used to identify security requirements for various critical infrastructure providers. We found that an access control system is a crucial security requirement for the surveyed critical infrastructure providers. Furthermore, the requirement analysis was used to propose a new criteria to evaluate access control systems for cloud computing. Moreover, this work presents a new cloud based access control model to meet the identified cloud access control requirements. The model does not only ensure the secure sharing of resources among potential untrusted tenants, but also has the capacity to support different access permissions for the same cloud user. Our focused in the proposed model is the lack of data isolation in lower levels (CPU caches), which could lead to bypass access control models to gain some sensitive information by using cache side-channel attacks. Therefore, the thesis investigates various real attack scenarios and the gaps in existing mitigation approaches. It presents a new Prime and Probe cache side-channel attack, which can give detailed information about addresses accessed by a virtual machine with no need for any information about cache sets accessed by the virtual machine. The design, implementation and evaluation of a proposed solution preventing cache side-channel attacks are also presented in the thesis. It is a new lightweight solution, which introduces very low overhead (less than 15,000 CPU cycles). It can be applied in any operating system and prevents cache side-channel attacks in cloud computing. The thesis also presents a new detecting cache side-channel attacks solution. It focuses on the infrastructure used to host cloud computing tenants by counting cache misses caused by a virtual machine. The detection solutions has 0% false negative and 15% false positive.

Traditional access control mechanisms prevent illegal access by controlling access right before executing an action; they belong to a class of a priori security solutions and, from this point of view, they have some limitations, like inflexibility in unanticipated circumstances. By contrast, a posteriori mechanisms enforce policies not by preventing unauthorized access, but rather by deterring it. Such access control needs evidence to prove violations. Evidence is derived from one or several log records, which trace each user's actions. Efficiency of violation detection mostly depends on the compliance of log records with the access control policy. In order to develop an efficient method for finding these violations, we propose restructuring log records according to a security policy model. We illustrate our methodology by applying it to the healthcare domain, taking care of the IHE (Integrating the healthcare enterprise) framework, particularly its basic security profile, ATNA (Audit Trail and Node Authentication). This profile defines log records established on the analysis of common health practice scenarios. We analyze and establish how ATNA log records can be refined in order to be integrated into an a posteriori access and usage control process, based on an expressive and contextual security policy like the OrBAC policy.

The increased complexity of modern access control (AC) systems stems partly from the need to support diverse and multiple administrative domains. Systems engineering is a key technology to manage this complexity since it is capable of assuring that an operational system will adhere to the initial conceptual design and defined requirements. Specifically, the verification stage of an AC system should be based on techniques that have a sound and mathematical underpinning. Working on this assumption, model checking techniques are applied for the verification of predefined system properties, and thus, conducting a security analysis of a system. In this paper, we propose the utilization of automated and error-free model checking techniques for the verification of security properties in multi-domain AC systems. Therefore, we propose a formal definition in temporal logic of four AC system properties regarding secure inter-operation with Role-Based Access Control (RBAC) policies in order to be verified by using model checking. For this purpose, we demonstrate the implementation of a tool chain for expressing RBAC security policies, reasoning on role hierarchies and properly feeding the model checking process. The proposed approach can be applied in any RBAC model to efficiently detect non-conformance between an AC system and its security specifications. As a proof of concept, we provide examples illustrating the verification of the defined secure inter-operation properties in multi-domain RBAC policies.

Access control system is an important component to protect patients’ information from abuse in a health care system. It is a major concern in the management, design, and development of healthcare systems. Designing access control policies for healthcare systems is complicated due to the dynamic and inherent complexity of the tasks performed by the healthcare personnel. Permissions in access control systems are usually granted on the basis of static policies. However, static policies are not enough to cope with various situations such as emergencies. Most often, the Break-the-glass mechanism is used to bypass static policies to handle emergency situations. Since healthcare systems are critical systems, where errors can be very costly in terms of lives, quality of life, and/or dollars, it is crucial to identify discrepancies between policy specifications and their intended function to implement correctly a flexible access control system. Formal verifications are necessary for exhaustive verification and validation of policy specifications to ensure that the policy specifications truly encapsulate the desires of the policy authors. We present a verifiable framework to enact a dynamic access control model by integrating the ANSI/INCTIS RBAC Reference Model in a workflow and an approach for property verifications of the access control model. Access control policies are expressed by the formal semantics of a model checker and properties are verified by the DiVinE model checker.

The Pi-calculus has been developed to reason about behavioural equivalence. Different notions of equivalence are defined in terms of process interactions, as well as the context of processes. There are various extensions of the Pi-calculus, such as the SPI calculus, which has primitives to facilitate security protocol design.<br /> <br />Another area of computer security is access control research, which includes problems of access control models, policies and access control mechanism. The design of a unified framework for access control requires that all policies are supported and different access control models are instantiated correctly.<br /> <br />In this paper we will utilise the Pi calculus to reason about access control policies and mechanism. An equivalence of different policy implementations, as well as access control mechanism will be shown. Finally some experiences regarding the use of Pi-calculus are presented.

: The discretionary access controls in today's computer systems are designed to enforce a specific access control policy. An application whose access control policies do not easily match the policy that is wired into the system is forced to work around that wired-in policy. As a result, the application itself must enforce discretionary security and cannot make use of the assurances of the computer system's discretionary access controls. This report presents a flexible approach to discretionary access control that allows the implementation of arbitrary access control policies. The generality of the approach allows a user to implement a discretionary access control policy that is tailored to an application, rather than having to work around a specific policy that is wired into the computer system. The report focuses on discretionary controls for object-oriented systems. Object-oriented systems are an emerging technology of great import for applications in business, industry, and the military. Many of these applications must share information among users with different needs and authorizations. The specific access rules desired will vary from application to application. Thus, a flexible approach to discretionary access control for such systems is proposed.

Access control (AC) is a computer security requirement used to control, in a computing environment, what the user can access, when and how. Policy administration is an essential feature of an AC system. As the number of computers are in hundreds of millions, and due to the different organization requirements, applications and needs, various AC models are presented in literature, such as: Discretionary Access Control (DAC), Mandatory Access Control (MAC), Role Based Access Control (RBAC), etc. These models are used to implement organizational policies that prevent the unauthorized disclosure of sensitive data, protecting the data integrity, and enabling secure access and sharing of information. Each AC model has its own methods for making AC decisions and policy enforcement. However, due to the diversity of AC models and the various concerns and restrictions, its essential to find AC metamodels with higher level of abstraction. Access control metamodels serve as a unifying framework for specifying any AC policy and should ease the migration from an AC model to another. This study reviews existing works on metamodels descriptions and representations. But, are the presented metamodels sufficient to handle the needed target of controlling access especially in the presence of the current information technologies? Do they encompass all features of other AC models? In this paper we are presenting a survey on AC metamodels.

SummaryThe block chain is the emerging domain that offers the features like shared, immutable, and decentralized dataset that saves the asset's history. Security and storage are the most challenging aspect. The classical techniques' issues and challenges are an encouragement for developing a fresh block chain‐assisted IPFS model with access control policies. Hence, this research paper introduces an effective access control and authentication based on an interplanetary file system (IPFS)‐based block chain and access control system for attaining secured transactions. The developed method comprises five entities, that is smart contract, data owner, data requester, block chain and IPFS along with eight phases, to be exact setup, user registration, initialization, storage and data encryption, authentication, testing, access control, and decryption phase, to provide better access control and storage capacity. The proposed IPFS‐based block chain and access control system offered effective storage and secure transactions in the block chain network. The highest detection rate (0.870), lowest communication overhead (0.766 MB), and highest privacy rate (0.719) are all achieved by the proposed IPFS‐based block chain and access control system.

PurposeThis paper aims to manage access control tasks to satisfy the user privacy needs of online information resources according to social relations and tags.Design/methodology/approachThe study proposes a method for access control management in the online social context. The proposed method includes the access control policy management process, metadata of access control policies, the data of ontologies, tags, and social relations, and conflict detection rules.FindingsOnline information sharing and hiding, which needs to consider social relations and mentioned topics, is a unique context and needs a novel access control mechanism. Ontologies are powerful and expressive enough to identify conflicts in access control policies. The paper provides a method using ontologies to control the access control activities based on social relations and tags on web content. The effectiveness of the method's conflict detection rules is validated through several scenarios.Research limitations/implicationsTo make the proposed method suitable for widespread usage, further work is required to develop an access control policy specification and conflict detection tool. The proposed method introduces relatively novel usage scenarios, which consider social relationships, and tags compared with existing access control methods for online information sharing.Practical implicationsThe proposed access control mechanism can be integrated into existing web sites. Online users can use this method to share information more easily than at present.Originality/valueThe method enables flexible access control in social contexts and handles unavoidable conflicts. It also opens the way to new access control scenarios in online social activities. The method can be used to keep secrets hidden from selected people.

Agile development has become increasingly popular among software development teams due to its capacity to deliver and update software rapidly while accommodating evolving requirements. Within this dynamic context, access control policies are critical for ensuring the security of systems by defining who can access specific resources under given conditions. However, identifying and documenting these policies often rely on manual, time-intensive processes prone to errors and oversight. This paper proposes an innovative framework leveraging Retrieval-Augmented Generation (RAG) and Large Language Models (LLMs) to automate the extraction and organization of access control policies from user stories and software documentation. The framework focuses on the early stages of the development lifecycle, capturing access control requirements as expressed in natural language artifacts. It comprises two core components: (1) a pipeline for extracting and categorizing access control policies, enabling precise mappings between roles, actions, and resources, and (2) an interactive chatbot designed to support Security Operations Center (SOC) analysts in evaluating suspicious access requests by providing contextualized insights into access policies. By integrating advanced natural language processing techniques with retrieval-based augmentation, the framework aims to reinforce access control mechanisms by improving visibility, and providing contextualized insights for security analysts.

Background: Cloud computing provides access to a large scale of resources. Access control is the indispensable requirement for protecting cloud resource. A cloud service provider is responsible for enforcing access control and they normally rely upon conventional access control mechanisms. Methods: These access control policies, consider the access control primitives in separation which may lead to abuse of access control. These aforesaid problems motivated our research to center around the provision of access control by considering the association among the three access control primitives namely the user making access request, resource upon which access is requested and operation performed by the user on the resource. Hence Ontology Centric Access Control (OCAC) is being proposed in this paper. Findings: This OCAC circulates authorization rules among the primitives of access control say subject, object and action by reducing the various associations among the associations among the access control elements; it is observed that there is less chance for security violation. Ontology is used since it reduces the times of agreement while exchanging the authorization policies across the security domains. For reducing the number of statements and rules in policy base, subsumption property is used. This reduces the space and time complexity. Applications/Improvements: We are applying our work to protect bank data as banks are embracing clouds to store huge data by cutting their IT costs.Keywords: Access Control, Ontology, Cloud Computing, User Ontology, Resource Ontology, Activity Ontology Introduction

One of the security issues in data outsourcing scenario is the enforcement of data owner's access control policies. This includes some challenges; namely, the number of keys required to access authorized resources, efficient policy updating, write access control enforcement, user and data owner overhead, and preserving confidentiality of data and policies. Most of the existing solutions address only some of the challenges, while they impose high overhead on both the data owner and users. Though, policy management in the Role-Based Access Control (RBAC) model is easier and more efficient due to the existence of role hierarchical structure and role inheritance; most of the existing solutions address only enforcement of policies in form of access control matrix. In this paper, we propose an approach to enforce RBAC policies on encrypted data outsourced to service provider (SP). We utilize Chinese Remainder Theorem (CRT) for key management and role/permission assignment. Efficient user revocation, support of role hierarchical structure updates, availability of authorized resources for users of newly added roles, and enforcement of write access control policies as well as static separation of duties (SSD), are of the proposed solution advantages. In addition, the ciphertext size is linearly proportional to the plaintext size, regardless of the number of roles and users.

We propose formal analysis of access control policies associated with business processes. Formal analysis of such policies enables us to investigate certain properties of interest and determine whether they hold. Discovering whether these policies create the intended effects, especially when the number of policies is increased and often composed, can become complex. In addition, we believe that access control policies must be specified in such a way that their integration into business processes is straightforward. Prior research has focused on formal verification of either access control policies or business processes but not viewed the two as an integrated whole. We show an approach in which access control policies and business processes are described using the same foundational building blocks, consequently, integration of access control policies and business processes is significantly less complex. Furthermore, access control policies can now be described by business patterns, and this description may result in discovery of access control patterns that can be used in the future. Finally, our approach through the use of business patterns is capable of modeling access control policies in the same way an access control model does. In addition, these policies can be specified and extended using rules, and in this respect, are akin to a policy language.

Cloud computing is considered one of the most dominant paradigms in the Information Technology (IT) industry these days. It offers new cost-effective services on-demand such as Software as a Service (SaaS), Infrastructure as a Service (IaaS) and Platform as a Service (PaaS). However, with all of these services promising facilities and benefits, there are still a number of challenges associated with utilizing cloud computing such as data security, abuse of cloud services, malicious insider and cyber-attacks. Among all security requirements of cloud computing, access control is one of the fundamental requirements in order to avoid unauthorized access to systems and protect organizations assets. Although, various access control models and policies have been developed such as Attribute based Access Control (ABAC) and Role Based Access Control (RBAC) for different environments, these models may not fulfil cloud’s access control requirements. In this paper, an enhanced attribute-based access control based on strategy mechanism is proposed by introducing a strategy for providing access control to the users in the cloud environment.

XACML is a powerful and flexible access control (AC) policy language. It is an OASIS standard that is now widely used in a variety of applications, particularly those that require inter-operability between AC systems. The language definition includes a precise grammar, syntax, and semantics, and it is both expressive and verbose. This combination of expressive power and verbosity can lead to difficulty in understanding the language's syntax and semantics for both technical and nontechnical users alike. As a result, reducing the difficulty of editing XACML policies has become an intense area of research. In our own work in this area, we previously showed how to render complex XACML conditions using a non-technical display notation and showed that it is easy to use this notation with interactive plain text editors that do not require any technical coding. Although XACML conditions are expressive and flexible, XACML targets are actually the most commonly used XACML language construct. They have an additional level of complexity, especially in version 3.0, due to the fact that the form and kinds of XACML constructs allowed in targets is much more limited. This paper extends our previous work, showing how the same powerful and flexible interactive editing principles can be applied to targets in order to allow users to use natural logic rather than implementation logic. We extend these principles and fully integrate them into our editing tool, easy XACML. This tool is usable by users with no technical knowledge of XACML, thus making XACML totally transparent to the user, while still retaining all of its functionalities and semantics. Our tool thus allows users to focus on policy logic rather than on details of syntax. As a result, the risk of errors in policies is greatly reduced.