Discretionary Security for Object-Oriented Database Systems

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.

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

ABSTRACTSome specific information or resources only can be accessed by authorized users. Discretionary access control (DAC), mandatory access control (MAC), and role‐based access control (RBAC) are three main classes of access control policies. MAC and RBAC are more secure than discretionary access control because a system instead of an object's owner determines the policy. MAC is appropriate for multilevel applications with high security requirements such as military ones, while RBAC provides security and business benefits. Most institutions, companies, and governments are multilevel, so relationships between roles or security levels tend to be hierarchical. In this work, an access control mechanism, providing explicit transitive exception and antisymmetric arrangement, is proposed to provide flexible and appropriate solutions to hierarchical relationships. For practicability, no access control policy is strictly constrained in the proposed mechanism such that security classes can be determined according to specific requirements. The proposed mechanism employs an elliptic curve cryptosystem and a two‐layer hash approach to ensure security and computation efficiency. Copyright © 2014 John Wiley & Sons, Ltd.

An access control system is a collection of rules used to restrict the visibility, access, and usage of the data resources in an institutional environment. When implemented, these rules provide a policy for achieving the security of the institution, establishing a hierarchy of the employees depending on their rights over the institution’s data resouces. An access control system is based on two fundamental concepts: authentication (that verifyies the user's identity) and authorization (that provides a hierarchy of the employees according to their access rights over the institutional resources). Among the most commonly used access control models we recall Role-Based Access Control (RBAC), in which users with the same role have equal access rights to data resources, Discretionary Access Control (DAC), in which the system owner decides which user has access to system resources, and Mandatory Access Control (MAC), in which a series of rules, with a high level of security established by a predefined authority, are used. In this article, we will study the last two models, namely DAC and MAC, along with their main implementations: Access Control Matrix and the Take-Grant models for DAC, BIBA and Bell-LaPadula for MAC.

Enormous popularity of Social Networking Sites has introduced a great number of privacy risks.Even the most popular of all the social networking sites have characterized access control policies in terms of explicit tracking of the interpersonal relationships between the subjects, objects and their inter relation.In this paper we present a novel paradigm that accounts for a secure, yet sociable information flow model based on access control policies.We took advantage of real time success of the access control security policies in operating systems by implementing them on online social networks at the mandatory level so that the user's privacy does not have to be at stake by the growth of social network and activities or by the level of user understanding of the privacy settings provided by the social networking sites based on discretionary access control.We used Facebook and Google+ as case study and implemented the security policy in SecureWall to mitigate possible privacy leakage scenarios observed.We have implemented Chinese wall policy for community level privacy, Bell la-Padulla access control model to assure confidentiality to the user and Biba Access control model for providing Integrity.Since Bell la-Padulla and Biba models are basically meant to serve military security and therefore can risk sociability, we have combined the two models using Lipner Security Matrix in order to provide security without risking sociability.Our research can be adopted by online social networking sites for the mandatory level security especially for social networking in organizational specific activities.

With the convenient connection to network, more and more individual information including sensitive information, such as contact list in Mobile Phone or PDA, can be delegated to the professional third service provider to manage and maintain. The benefit of this paradigm is, on one hand to avoid the sensitive information leakage when individual devices failed or lost, on the other hand to make only the authorized users access and share the delegated information online anytime and anywhere. However, in this paradigm the critical problems to be resolved are to guarantee both the privacy of delegated individual information and the privacy of authorized users, and what is more important to afford the owners of communication devices to have high level of control and power to create their own particular access control policies. In this paper, we present an approach to implement the personalized access control at third service provider in a privacy preserving way. Our approach implements the critical problems above in this paradigm by using selective encryption, blind signature and the combination of role based access control and discretionary access control.

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 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.

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.

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.

One of the main requirements for providing software security is the enforcement of access control policies which aim to protect resources of the system against unauthorized accesses. Any error in the implementation of such policies may lead to undesirable outcomes. For testing the implementation of access control policies, it is preferred to use automated methods which are faster and more reliable. Although several researches are conducted for automated testing of the specification of access control policies at the design phase, there is not enough research on testing their implementation. In addition, since access control is amongst non-functional requirements of the system, it is not easy to test them along with other requirements of the system by usual methods. To address this challenge, in this paper, we propose an automated method for testing the implementation of access control in a system. This method, as a model based technique, is able to extract test cases for evaluating the access control policies of the system under test. To generate test cases automatically, a combination of behavior model of the system and the specification of access control policies are used. The experimental results show that the proposed approach is able to find the failures and cover most of the code that is related to access control policies.

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.

Role-based access control (RBAC) is useful in information security. It is a super set of discretionary access control (DAC) and mandatory access control (MAC). Since DAC and MAC are useful in information flow control (which protects privacy within an application), RBAC can certainly be used in that control. Our research reveals that different control granularity is needed in different cases when controlling information flows within an application. An information flow control model should thus simultaneously offer different levels of control granularity. We designed a multipleleveled RBAC model to offer multiple levels of control granularity, in which a level of RBAC controls a level of granularity. We called the model L n RBAC (n-leveled RBAC), which offer the following features: (1) it allows different control granularity in different cases, (2) it solves the covert channel problems caused by abnormal program stopping, (3) it adapts to dynamic object state change, (4) it controls method invocation through argument sensitivity (5) it allows purpose-oriented method invocation, (6) it controls write access precisely, and (7) it avoids Trojan horses. We implemented a prototype for L n RBAC and evaluated it. This paper presents L n RBACL.

The Windows Embedded operating system (OS) adopts a discretionary access control (DAC)-based policy, but underlying vulnerabilities exist because of external hacker attacks and other factors. In this study, we propose a system that improves the security of the Windows Embedded OS by applying a mandatory access control (MAC) policy in which the access rights of objects, such as files and folders, and subjects’ privileges, such as processes, are compared. We conducted access control tests to verify whether the proposed system could avoid the vulnerabilities of DAC-based systems. Our results indicate that the existing DAC-based security systems could be neutralized if a principal’s security policy is removed. However, in the proposed MAC-based Windows Embedded OS, even if the clearance and category values of a subject’s files are given the highest rating, all accesses are automatically denied. Therefore, the execution of all files that were not previously registered on the whitelist was denied, proving that security was improved relative to DAC-based systems.

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.