A non-technical XACML target editor for dynamic access control systems

Cloud computing paradigm is still an evolving paradigm but has recently gained tremendous momentum due to its potential for significant cost reduction and increased operating efficiencies in computing. However, its unique aspects exacerbate security and privacy challenges that pose as the key roadblock to its fast adoption. Cloud computing has already become very popular, and practitioners need to provide security mechanisms to ensure its secure adoption. In this chapter, the authors discuss access control systems and policy management in cloud computing environments. The cloud computing environments may not allow use of a single access control system, single policy language, or single management tool for the various cloud services that it offers. Currently, users must use diverse access control solutions available for each cloud service provider to secure data. Access control policies may be composed in incompatible ways because of diverse policy languages that are maintained separately at every cloud provider. Heterogeneity and distribution of these policies pose problems in managing access policy rules for a cloud environment. In this chapter, the authors discuss challenges of policy management and introduce a cloud based policy management framework that is designed to give users a unified control point for managing access policies to control access to their resources no matter where they are stored.

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.

ABSTRACTCognitive radio is a novel wireless communication technology that allows for adaptive configuration of the reception parameters of a terminal, based on the information collected from the environment. Cognitive radio technology can be used in innovative spectrum management approaches such as spectrum sharing, where radio frequency spectral bands can be shared among various users through a dynamic exclusive‐use spectrum access model. Spectrum sharing can be applied to various scenarios in the commercial, public safety and military domain. In some scenarios, spectrum sharing demands a mechanism for expressing and enforcing access control policies for the allocation of resources including spectral bands. The access control polices should state what are the available resources (e.g., transmission/reception bandwidths), what are the users that are allowed to access them and under what conditions. However, because of the intrinsically highly dynamic nature of specific scenarios (e.g., public safety, military), where parties with various levels of authority may suddenly appear, it may be difficult to establish in advance what are the most suitable access control policies. Trust negotiation is a well‐known approach for expressing and enforcing distributed access control policies that depend on two or more parties. In this work, we present a trust negotiation‐based framework that allows for the definition of highly expressive and flexible distributed access control policies for the allocation of spectrum resources. Copyright © 2012 John Wiley & Sons, Ltd.

In recent years we have seen significant advances in the technology used to both publish and consume structured data using the existing web infrastructure, commonly referred to as the Linked Data Web. However, in order to support the next generation of e-business applications on top of Linked Data suitable forms of access control need to be put in place. This paper provides an overview of the various access control models, standards and policy languages, and the different access control enforcement strategies for the Resource Description Framework (the data model underpinning the Linked Data Web). A set of access control requirements that can be used to categorise existing access control strategies is proposed and a number of challenges that still need to be overcome are identified.

In an open source cloud computing platform such as OpenStack, operators use Role-Based Access Control (RBAC) model to grant access to cloud resources. However, these user-level role-based access control techniques fail to include comprehensive user context. We believe a situational aware framework will improve security by bringing in user's context to such cloud systems. In this paper, we create a semantically rich context-sensitive access control system for OpenStack by incorporating the user's current context attributes like location, time, etc. In a proof-of-concept implementation, we integrate a knowledge graph with our own access control system to express and enforce the contextual-situation policies in OpenStack. The proposed system provides enhanced, flexible access control while minimizing the overhead of altering the existing access control framework. We also discuss various use cases, to highlight the benefits of our system and show enforcement results.

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.

Light-weight, flexible access control, which allows software to regulate reads and writes to any granularity of memory region, can help improve the reliability of today's multi-module multi-programmer applications, as well as the efficiency of software debugging tools. Unfortunately, access control in today's processors is tied to support for virtual memory, making its use both heavy weight and coarse grain. In this paper, we propose Sentry, an auxiliary level of virtual memory tagging that is entirely subordinate to existing virtual memory-based protection mechanisms and can be manipulated at the user level. We implement these tags in a complexity-effective manner using an M-cache (metadata cache) structure that only intervenes on L1 misses, thereby minimizing changes to the processor core. Existing cache coherence states are repurposed to implicitly validate permissions for L1 hits. Sentry achieves its goal of flexible and light-weight access control without disrupting existing inter-application protection, sidestepping the challenges associated with adding a new protection framework to an existing operating system. We illustrate the benefits of our design point using 1) an Apache-based web server that uses the M-cache to enforce protection boundaries among its modules and 2) a watchpoint-based tool to demonstrate low-overhead debugging. Protection is achieved with very few changes to the source code, no changes to the programming model, minimal modifications to the operating system, and with low overhead incurred only when accessing memory regions for which the additional level of access control is enabled.

Cloud computing plays a major role in sharing data and resources to other devices through data outsourcing. During sharing resources, it is a challenging task to provide access control and secure write operations. The main issue is to provide secure read and write operations collaboratively and to reduce computational overload by effective key management. In this paper, a secure and an efficient data collaboration scheme blowfish hybridized weighted attribute-based Encryption (BH-WABE ) for secure data writing and proficient access control has been proposed. Here, weight is assigned to each attribute based on its importance and data are encrypted using access control policies. The cloud service provider stores the outsourced data and an attribute authority revokes or updates the attributes by assigning different attributes based on the weight. The receiver can access the data file corresponding to its weight in order to reduce the computational overload. The proposed BH-WABE provides collusion resistance, multiauthority security and fine-grained access control in terms of security, reliability, and efficiency. The performance is compared with the conventional hybrid attribute-based encryption (HABE) scheme in terms of data confidentiality, flexible access control, data collaboration, full delegation, partial decryption, verification, and partial signing.

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.

PurposeProvide a secure solution for web services (WS). A new interoperable and distributed access control for WS is presented.Design/methodology/approachBased on the separation of the access control (AC) and authorization function.FindingsMechanisms presented allow seamless integration of external authorization entities in the AC system. The Semantic Policy Language (SPL) developed facilitates specification of policies and semantic policy validation. SPL specifications are modular and can be composed without ambiguity. Also addressed was the problem of the association of policies to resources (WS or their operations) in a dynamic, flexible and automated way.Research limitations/implicationsThe ACProxy component is currently under development. Ongoing work is focused on achieving a richer “use control” for some types of WS.Practical implicationsAdministrators of WS can specify AC policies and validate them to find syntactic and semantic errors. Components for automated validation of policies at different levels are included. This ensures that the AC policies produce the desired effects, facilitating the creation and maintenance of policies. It also provides mechanisms for the use of interoperable authorizations.Originality/valueA practical system that provides a secure solution to AC for WS. To the best of one's knowledge, no other system provides mechanisms for semantic validation of policies based on external authorization entities. Likewise, the mechanisms for interoperability of external authorization entities are also novel. The system provides content‐based access control and a secure, decentralized and dynamic solution for authorization that facilitates the management of complex systems and enhances the overall security of the AC.

Recently, mobile devices with wireless LAN function become widely used as communication tools. These devices are also recognized to be useful for communication and information gathering at stations and refuges in case of emergency such as disaster, so each institution is expected to temporarily open its access points (APs) for all users in such cases. However, for security, each institution needs to properly control their accesses according users. In addition, since a lot of people access through an AP at refuges, it is important to prioritize significant data packets. Now, we propose a flexible access and priority control system based on 802.1X authentication in time of disaster.

Directory Systems to support communications networks are currently the subject of serious international standardization efforts. The most recent CCITT and ISO proposals for Directory Systems are summarized, and within this context the requirements for flexible and robust access control mechanisms are examined. The existence of varied access control policies at the international, national and local levels and the need to maintain the integrity of Directory System information are identified as major factors determining access control procedures. Techniques are suggested for access control mechanisms capable of capturing and enforcing the relevant access control semantics at each network site.

Towards more pro-active access control in computer systems and networks

In traditional framework, mandatory access control (MAC) system and malicious software are run in kernel mode. Malicious software can stop MAC systems to be started and make it do invalid. This problem cannot be solved under the traditional framework if the operating system (OS) is comprised since malwares are running in ring0 level. In this paper, we propose a novel way to use hypervisors to protect kernel integrity and the access control system in commodity operating systems. We separate the access control system into three parts: policy management (PM), security server (SS) and policy enforcement (PE). Policy management and the security server reside in the security domain to protect them against malware and the isolation feather of the hypervisor can protect them from attacks. We add an access vector cache (AVC) between SS and PE in the guest OS, in order to speed up communication between the guest OS and the security domain. The policy enforcement module is retained in the guest OS for performance. The security of AVC and PE can be ensured by using a memory protection mechanism. The goal of protecting the OS kernel is to ensure the security of the execution path. We implement the system by a modified Xen hypervisor. The result shows that we can secure the security of the access control system in the guest OS with no overhead compared with modules in the latter. Our system offers a centralized security policy for virtual domains in virtual machine environments.