Parichehr Dadkhah; Mohammad Dakhilalian; Parvin Rastegari
Abstract
Wireless Body Area Networks (WBANs) have attracted a lot of attention in recent researches as they play a vital role in diagnosing, controlling and treating diseases. These networks can improve the quality of medical services by following the health status of people and providing online medical advice ...
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Wireless Body Area Networks (WBANs) have attracted a lot of attention in recent researches as they play a vital role in diagnosing, controlling and treating diseases. These networks can improve the quality of medical services by following the health status of people and providing online medical advice for them, momentarily. Despite the numerous advantages of these networks, they may cause irrecoverable problems for patients, if security considerations are not properly met. So, it is very important to find solutions for satisfying security requirements in these networks. A signcryption scheme can be considered as one of the most important cryptographic tools for providing the security requirements in WBANs. Recently, Kasyoka et al. proposed a signcryption scheme based on which they designed an access control protocol for WBANs. They proved the security of their proposals in the random oracle model (ROM). In this paper, we concentrate on Kasyoka et al.’s proposals and show that their proposed signcryption scheme and consequently their proposed access control protocol for WBANs are vulnerable against various attacks, in contrast to their claims. Afterward, we fix the scheme to be secure against our proposed attacks.
Mohammad Ali Hadavi; Arash Bagherdaei; Simin Ghasemi
Volume 13, Issue 2 , July 2021, , Pages 117-129
Abstract
< p>Automatic detection of access control violations in software applications is a challenging problem. Insecure Direct Object Reference (IDOR) is among top-ranked vulnerabilities, which violates access control policies and cannot be yet detected by automated vulnerability scanners. While such ...
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< p>Automatic detection of access control violations in software applications is a challenging problem. Insecure Direct Object Reference (IDOR) is among top-ranked vulnerabilities, which violates access control policies and cannot be yet detected by automated vulnerability scanners. While such tools may detect the absence of access control by static or dynamic testing, they cannot verify if it is properly functioning when it is present. When a tool detects requesting access to an object, it is not aware of access control policies to infer whether the request is permitted. This completely depends on the access control logic and there is no automatic way to fully and precisely capture it from software behavior. Taking this challenge into consideration, this article proposes a black-box method to detect IDOR vulnerabilities in web applications without knowing access control logic. To this purpose, we first, gather information from the web application by a semi-automatic crawling process. Then, we tricksily manipulate legal requests to create effective attacks on the web application. Finally, we analyze received responses to check whether the requests are vulnerable to IDOR. The detection process in the analysis phase is supported by our set theory based formal modeling of such vulnerabilities. The proposed method has been implemented as an IDOR detection tool (IDOT) and evaluated on a couple of vulnerable web applications. Evaluation results show that the method can effectively detect IDOR vulnerabilities provided that enough information is gathered in the crawling phase.
Maryam Zarezadeh; Maede Ashouri-Talouki; Mohammad Siavashi
Abstract
Electronic health record (EHR) system facilitates integrating patients' medical information and improves service productivity. However, user access to patient data in a privacy-preserving manner is still challenging problem. Many studies concerned with security and privacy in EHR systems. Rezaeibagha ...
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Electronic health record (EHR) system facilitates integrating patients' medical information and improves service productivity. However, user access to patient data in a privacy-preserving manner is still challenging problem. Many studies concerned with security and privacy in EHR systems. Rezaeibagha and Mu [1] have proposed a hybrid architecture for privacy-preserving accessing patient records in a cloud system. In their scheme, encrypted EHRs are stored in multiple clouds to provide scalability and privacy. In addition, they considered a role-based access control (RBAC) such that for any user, an EHR access policy must be determined. They also encrypt the EHRs by the public keys of all users. So, for a large amount of EHRs, this scheme is not efficient. Furthermore, using RBAC for access policy makes the policy changing difficult. In their scheme, users cannot search on encrypted EHRs based on diseases and some physicians must participate in the data retrieval by a requester physician. In this paper, we address these problems by considering a ciphertext-policy attribute-based encryption (CP-ABE) which is conceptually closer to the traditional access control methods such as RBAC. Our secure scheme can retrieve encrypted EHR based on a specific disease. Furthermore, the proposed scheme guarantees the user access control and the anonymity of the user or data owner during data retrieval. Moreover, our scheme is resistant against collusion between unauthorized retrievers to access the data. The analysis shows that our scheme is secure and efficient for cloud-based EHRs.
N. Soltani; R. Bohlooli; R. Jalili
Abstract
One of the security issues in data outsourcing is the enforcement of the data owner’s access control policies. This includes some challenges. The first challenge is preserving confidentiality of data and policies. One of the existing solutions is encrypting data before outsourcing which brings ...
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One of the security issues in data outsourcing is the enforcement of the data owner’s access control policies. This includes some challenges. The first challenge is preserving confidentiality of data and policies. One of the existing solutions is encrypting data before outsourcing which brings new challenges; namely, the number of keys required to access authorized resources, efficient policy updating, write access control enforcement, overhead of accessing/processing data at the user/owner side. Most of the existing solutions address only some of the challenges, while imposing high overhead on both 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 the form of access control matrix. In this paper, we propose an approach to enforce RBAC policies on encrypted data outsourced to a service provider. We utilize Chinese Remainder Theorem for key management and role/permission assignment. Efficient user revocation, efficient role hierarchical structure updating, availability of authorized resources for users of new roles, and enforcement of write access control policies as well as static separation of duties, are of advantages of the proposed solution.
M. Amini; M. Arasteh
Abstract
A Virtual Organization (VO) consists of some real organizations with common interests, which aims to provide inter organizational associations to reach some common goals by sharing their resources with each other. Providing security mechanisms, and especially a suitable access control mechanism, which ...
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A Virtual Organization (VO) consists of some real organizations with common interests, which aims to provide inter organizational associations to reach some common goals by sharing their resources with each other. Providing security mechanisms, and especially a suitable access control mechanism, which enforces the defined security policy is a necessary requirement in VOs. Since VO is a complex environment with the huge number of users and resources, traditional access control models cannot satisfy VOs security requirements. Most of the current proposals are basically based on the attributes of users and resources. In this paper, we suggest using a combination of the semantic based access control (SBAC) model, and the attribute based access control (ABAC) model with the shared ontology of subjects' attributes in VOs. In this model, each participating organization makes its access control decisions according to an enhanced model of the ABAC model. However, access decision in the VO is made in more abstract level through an enhanced model of the SBAC model. Using the ontology of users and resources in this model facilitates access control in large scale VOs with numerous organizations. By the combination of SBAC and ABAC, we attain their benefits and eliminate their shortcomings. In order to show the applicability of the proposed model, an access control system, based on the proposed model, has been implemented in Java using available APIs, including Sun's XACML API, Jena, Pellet, and Protégé.
S. Shokrollahi; F. Shams; J. Esmaeili
Abstract
The primary characteristic of an Ultra-Large-Scale (ULS) system is ultra-large size on any related dimension. A ULS system is generally considered as a system-of-systems with heterogeneous nodes and autonomous domains. As the size of a system-of-systems grows, and interoperability demand between ...
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The primary characteristic of an Ultra-Large-Scale (ULS) system is ultra-large size on any related dimension. A ULS system is generally considered as a system-of-systems with heterogeneous nodes and autonomous domains. As the size of a system-of-systems grows, and interoperability demand between sub-systems is increased, achieving more scalable and dynamic access control system becomes an important issue. The Attribute-Based Access Control (ABAC) model is a proper candidate to be used in such an access control system. The correct deployment and enforcement of ABAC policies in a ULS system requires secure and scalable collaboration among different distributed authorization components. A large number of these authorization components should be able to join different domains dynamically and communicate with each other anonymously. Dynamic configuration and reconfiguration of authorization components makes authorization system more complex to manage and maintain in a ULS system. In this paper, an access control middleware is proposed to overcome the complexity of deployment and enforcement of ABAC policies in ULS systems. The proposed middleware is data-centric and consists of two layers. The lower layer is a Data-Distribution-Service (DDS) middleware used for loosely-coupled-communication among authorization components. The upper layer is used for secure configuration and reconfiguration of authorization components. An executable model of the proposed middleware is also represented by a Colored-Petri-Net (CPN) model. This executable model is used to analyze the behavior of the proposed middleware.
F. Raji; A. Miri; M. Davarpanah Jazi
Abstract
There are some critical privacy concerns in the current online social networks (OSNs). Users' information is disclosed to different entities that they were not supposed to access. Furthermore, the notion of friendship is inadequate in OSNs since the degree of social relationships between users dynamically ...
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There are some critical privacy concerns in the current online social networks (OSNs). Users' information is disclosed to different entities that they were not supposed to access. Furthermore, the notion of friendship is inadequate in OSNs since the degree of social relationships between users dynamically changes over the time. Additionally, users may define similar privacy settings for their friends in an OSN. In this paper, we present a centralized privacy-preserving framework for OSNs to address these issues. Using the proposed approach, the users enforce confidentiality and access control on the shared data while their connections/relationships with other users are kept anonymous in OSNs. In this way, the users themselves create and modify personalized privacy settings for their shared data while employing each other's privacy settings. Detailed evaluations of the proposed framework show the advantages of the proposed architecture compared to the most analogous recent approach.
A. Javadi; M. Amini
Abstract
Access control in open and dynamic Pervasive Computing Environments (PCEs) is a very complex mechanism and encompasses various new requirements. In fact, in such environments, context information should be used in access control decision process; however, it is not applicable to gather all context information ...
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Access control in open and dynamic Pervasive Computing Environments (PCEs) is a very complex mechanism and encompasses various new requirements. In fact, in such environments, context information should be used in access control decision process; however, it is not applicable to gather all context information completely and accurately all the time. Thus, a suitable access control model for PCEs not only should be context-aware, but also must be able to deal with imperfect context information. In addition, due to the diversity and heterogeneity of resources and users and their security requirements in PCEs, supporting exception and default policies is a necessary requirement. In this paper, we propose a Semantic-Aware Role-Based Access Control (SARBAC) model satisfying the aforementioned requirements using MKNF+. The main contribution of our work is defining an ontology for context information along with using MKNF+ rules to define context-aware role activation and permission assignment policies. Dividing role activation and permission assignment policies into three layers and using abstract and concrete predicates not only make security policy specification more flexible and manageable, but also make definition of exception and default polices possible. The expressive power of the proposed model is demonstrated through a case study in this paper.
F. Salim; J. Reid; E. Dawson
Abstract
This article presents a survey of authorization models and considers their 'fitness-for-purpose' in facilitating information sharing. Network-supported information sharing is an important technical capability that underpins collaboration in support of dynamic and unpredictable activities such as emergency ...
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This article presents a survey of authorization models and considers their 'fitness-for-purpose' in facilitating information sharing. Network-supported information sharing is an important technical capability that underpins collaboration in support of dynamic and unpredictable activities such as emergency response, national security, infrastructure protection, supply chain integration and emerging business models based on the concept of a 'virtual organization'. The article argues that present authorization models are inflexible and poorly scalable in such dynamic environments due to their assumption that the future needs of the system can be predicted, which in turn justifies the use of persistent authorization policies. The article outlines the motivation and requirement for a new flexible authorization model that addresses the needs of information sharing. It proposes that a flexible and scalable authorization model must allow an explicit specification of the objectives of the system and access decisions must be made based on a late trade-off analysis between these explicit objectives. A research agenda for the proposed Objective-Based Access Control concept is presented.
S. Sadat Emami; S. Zokaei
Abstract
Resources and services are accessible in pervasive computing environments from anywhere and at any time. Also, due to ever-changing nature of such environments, the identity of users is unknown. However, users must be able to access the required resources based on their contexts. These and other similar ...
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Resources and services are accessible in pervasive computing environments from anywhere and at any time. Also, due to ever-changing nature of such environments, the identity of users is unknown. However, users must be able to access the required resources based on their contexts. These and other similar complexities necessitate dynamic and context-aware access control models for such environments. In other words, an efficient access control model for pervasive computing environments should be aware of context information. Changes in context information imply some changes in the users' authorities. Accordingly, an access control model for a pervasive computing environment should control all accesses of unknown users to the resources based upon the participating context information, i.e., contexts of the users, resources and the environment. In this paper, a new context-aware access control model is proposed for pervasive computing environments. Contexts are classified into long-term contexts (which do not change during a session) and short-term contexts (which their steady-state period is less than an average time of a session). The model assigns roles to a user dynamically at the beginning of their sessions considering the long-term contexts. However, during a session the active permission set of the assigned roles are determined based on the short-term context conditions. Formal specification of the proposed model as well as the proposed architecture are presented in this paper. Furthermore, by presenting a real case study, it is shown that the model is applicable, decidable, and dynamic. Expressiveness and complexity of the model is also evaluated.