A FIREWALL MODEL OF FILE SYSTEM SECURITY

File system security is fundamental to the security of UNIX and Linux systems since in these systems almost everything is in the form of a file. To protect the system files and other sensitive user files from unauthorized accesses, certain security schemes are chosen and used by different organizations in their computer systems. A file system security model provides a formal description of a protection system. Each security model is associated with specified security policies which focus on one or more of the security principles: confidentiality, integrity and availability. The security policy is not only about “who” can access an object, but also about “how” a subject can access an object. To enforce the security policies, each access request is checked against the specified policies to decide whether it is allowed or rejected. The current protection schemes in UNIX/Linux systems focus on the access control. Besides the basic access control scheme of the system itself, which includes permission bits, setuid and seteuid mechanism and the root, there are other protection models, such as Capabilities, Domain Type Enforcement (DTE) and Role-Based Access Control (RBAC), supported and used in certain organizations. These models protect the confidentiality of the data directly. The integrity of the data is protected indirectly by only allowing trusted users to operate on the objects. The access control decisions of these models depend on either the identity of the user or the attributes of the process the user can execute, and the attributes of the objects. Adoption of these sophisticated models has been slow; this is likely due to the enormous complexity of specifying controls over a large file system and the need for system administrators to learn a new paradigm for file protection. We propose a new security model: file system firewall. It is an adoption of the familiar network firewall protection model, used to control the data that flows between networked computers, toward file system protection. This model can support decisions of access control based on any system generated attributes about the access requests, e.g., time of day. The access control decisions are not on one entity, such as the account in traditional discretionary access control or the domain name in DTE. In file system firewall, the access decisions are made upon situations on multiple entities. A situation is programmable with predicates on the attributes of subject, object and the system. File system firewall specifies the appropriate actions on these situations. We implemented the prototype of file system firewall on SUSE Linux. Preliminary results of performance tests on the prototype indicate that the runtime overhead is acceptable. We compared file system firewall with TE in SELinux to show that firewall model can accommodate many other access control models. Finally, we show the ease of use of firewall model. When firewall system is restricted to specified part of the system, all the other resources are not affected. This enables a relatively smooth adoption. This fact and that it is a familiar model to system administrators will facilitate adoption and correct use. The user study we conducted on traditional UNIX access control, SELinux and file system firewall confirmed that. The beginner users found it easier to use and faster to learn then traditional UNIX access control scheme and SELinux

Functionality-based application confinement: A parameterised and hierarchical approach to policy abstraction for rule-based application-oriented access controls

Access controls are traditionally designed to protect resources from users, and consequently make access decisions based on the identity of the user, treating all processes as if they are acting on behalf of the user that runs them. However, this user-oriented approach is insufficient at protecting against contemporary threats, where security compromises are often due to applications running malicious code, either due to software vulnerabilities or malware. Application-oriented access controls can mitigate this threat by managing the authority of individual applications. Rule-based application-oriented access controls can restrict applications to only allow access to the specific finely-grained resources required for them to carry out their tasks, and thus can significantly limit the damage that can be caused by malicious code. Unfortunately existing application-oriented access controls have policy complexity and usability problems that have limited their use. This thesis proposes a new access control model, known as functionality-based application confinement (FBAC). The FBAC model has a number of unique features designed to overcome problems with previous approaches. Policy abstractions, known as functionalities, are used to assign authority to applications based on the features they provide. Functionalities authorise elaborate sets of finely grained privileges based on high-level security goals, and adapt to the needs of specific applications through parameterisation. FBAC is hierarchical, which enables it to provide layers of abstraction and encapsulation in policy. It also simultaneously enforces the security goals of both users and administrators by providing discretionary and mandatory controls. An LSM-based (Linux security module) prototype implementation, known as FBAC-LSM, was developed as a proof-of-concept and was used to evaluate the new model and associated techniques. The policy requirements of over one hundred applications were analysed, and policy abstractions and application policies were developed. Analysis showed that the FBAC model is capable of representing the privilege needs of applications. The model is also well suited to automaiii tion techniques that can in many cases create complete application policies a priori, that is, without first running the applications. This is an improvement over previous approaches that typically rely on learning modes to generate policies. A usability study was conducted, which showed that compared to two widely-deployed alternatives (SELinux and AppArmor), FBAC-LSM had significantly higher perceived usability and resulted in significantly more protective policies. Qualitative analysis was performed and gave further insight into the issues surrounding the usability of application-oriented access controls, and confirmed the success of the FBAC model

A Secure Reconfigurable System-On-Programmable-Chip Computer System

A System-on-Programmable-Chip (SoPC) architecture is designed to meet two goals: to provide a role-based secure computing environment and to allow for user reconfiguration. To accomplish this, a secure root of trust is derived from a fixed architectural subsystem, known as the Security Controller. It additionally provides a dynamically configurable single point of access between applications developed by users and the objects those applications use. The platform provides a model for secrecy such that physical recovery of any one component in isolation does not compromise the system. Dual-factor authentication is used to verify users. A model is also provided for tamper reaction. Secure boot, encrypted instruction, data, and Field Programmable Gate Array (FPGA) configuration are also explored. The system hardware is realized using Altera Avalon SoPC with a NIOS II processor and custom hardware acting as the Security Controller and a second NIOS II acting as the subject application configuration. A DE2 development kit from Altera hosting a Cyclone II FPGA is used along with a Secure Digital (SD) card and a custom printed circuit board (PCB) containing a second Cyclone II to demonstrate the system. User applications were successfully run on the system which demonstrated the secure boot process, system tamper reaction, dynamic role-based access to the security objects, dual-factor authentication, and the execution of encrypted code by the subject processor. Simulations provided detailed examinations of the system execution. Actual tests were conducted on the physical hardware successfully

DR BACA: dynamic role based access control for Android

Thesis (M.S.)--Boston UniversityAndroid, as an open platform, dominates the booming mobile market. However, its permission mechanism is inflexible and often results in over-privileged applications. This in turn creates severe security issues. Aiming to support the Principle of Least Privilege, we propose a Dynamic Role Based Access Control for Android (DR BACA) model and implement the DR BACA system to address these problems. Our system offers multi-user management on Android mobile devices, comparable to traditional workstations, and provides fine-grained Role Based Access Control (RBAC) to en- hance Android security at both the application and permission level. Moreover, by leveraging context-aware capabilities of mobile devices and Near Field communication (NFC) technology, our solution supports dynamic RBAC that provides more flexible access control while still being able to mitigate some of the most serious security risks on mobile devices. The DR BACA system is highly scalable, suitable for both end- users and large business environments. It simplifies configuration and management of Android devices and can help enterprises to deal with security issues by implementing a uniform security policy. We show that our DR BACA system can be deployed and used with eet:se. With a proper security policy, our evaluation shows that DR BACA can effectively mitigate the security risks posed by both malicious and vulnerable non-malicious applications while incurring only a small overall system overhead

USING BLOCKCHAIN TO BUILD DECENTRALIZED ACCESS CONTROL IN A PEER-TO-PEER E-LEARNING PLATFORM

In the context of E-learning platforms, the amount of research focusing on access control is proliferating. However, research related to the decentralized access control in this field is scarce. To improve such area of research, an innovative model of decentralized access control used to protect the collaborative peer-to-peer E-learning platform has been proposed. In this model, the integrity, authenticity, non-repudiation and traceability of E-learning resources are ensured by using Blockchain platform. Also, RESTful web service and Go/Java programming language will be used as tools to implement this model. A key metric is measured to evaluate the proposed model: average response time. To increase the accuracy, some experiments (144) have been carried out. The same experiment is conducted in two comparatively different network environment: Local Area Network (LAN) and Cloud Web Service (such as Amazon Web Service). LAN running environment represents the optimal condition while Cloud environment stands for the actual condition in the real world. When the number of clients in my proposed E-learning platform is relatively small (consisting of one to thirty concurrent clients interacting with E-learning resources), the average response time in the LAN environment is much faster (nearly 1.5 times) than that in Cloud environment. Nevertheless, when the number of clients is on a large scale, the difference of average response time between this two environment becomes insignificant. Besides, adding servers in both environments can increase the horizontal scalability. Furthermore, adding servers in Cloud environment can boost the system performance dramatically. However, extending the delay could have an impact on the system performance but negligible

A Collaborative Access Control Model for Shared Items in Online Social Networks

The recent emergence of online social networks (OSNs) has changed the communication behaviors of thousand of millions of users. OSNs have become significant platforms for connecting users, sharing information, and a valuable source of private and sensitive data about individuals. While OSNs insert constantly new social features to increase the interaction between users, they, unfortunately, offer primitive access control mechanisms that place the burden of privacy policy configuration solely on the holder who has shared data in her/his profile regardless of other associated users, who may have different privacy preferences. Therefore, current OSN privacy mechanisms violate the privacy of all stakeholders by giving one user full authority over another’s privacy settings, which is extremely ineffective. Based on such considerations, it is essential to develop an effective and flexible access control model for OSNs, accommodating the special administration requirements coming from multiple users having a variety of privacy policies over shared items. In order to solve the identified problems, we begin by analyzing OSN scenarios where at least two users should be involved in the access control process. Afterward, we propose collaborative access control framework that enables multiple controllers of the shared item to collaboratively specify their privacy settings and to resolve the conflicts among co-controllers with different requirements and desires. We establish our conflict resolution strategy’s rules to achieve the desired equilibrium between the privacy of online users and the utility of sharing data in OSNs. We present a policy specification scheme for collaborative access control and authorization administration. Based on these considerations, we devise algorithms to achieve a collaborative access control policy over who can access or disseminate the shared item and who cannot. In our dissertation, we also present the implementation details of a proof-of-concept prototype of our approach to demonstrate the effectiveness of such an approach. With our approach, sharing and interconnection among users in OSNs will be promoted in a more trustworthy environment

Analyzing and developing role-based access control models

Role-based access control (RBAC) has become today's dominant access control model, and many of its theoretical and practical aspects are well understood. However, certain aspects of more advanced RBAC models, such as the relationship between permission usage and role activation and the interaction between inheritance and constraints, remain poorly understood. Moreover, the computational complexity of some important problems in RBAC remains unknown. In this thesis we consider these issues, develop new RBAC models and answer a number of these questions. We develop an extended RBAC model that proposes an alternative way to distinguish between activation and usage hierarchies. Our extended RBAC model has well-defined semantics, derived from a graph-based interpretation of RBAC state. Pervasive computing environments have created a requirement for access control systems in which authorization is dependent on spatio-temporal constraints. We develop a family of simple, expressive and flexible spatio-temporal RBAC models, and extend these models to include activation and usage hierarchies. Unlike existing work, our models address the interaction between spatio-temporal constraints and inheritance in RBAC, and are consistent and compatible with the ANSI RBAC standard. A number of interesting problems have been defined and studied in the context of RBAC recently. We explore some variations on the set cover problem and use these variations to establish the computational complexity of these problems. Most importantly, we prove that the minimal cover problem -- a generalization of the set cover problem -- is NP-hard. The minimal cover problem is then used to determine the complexity of the inter-domain role mapping problem and the user authorization query problem in RBAC. We also design a number of efficient heuristic algorithms to answer the minimal cover problem, and conduct experiments to evaluate the quality of these algorithms.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Developing Single Use Server Containers

The security provided by virtualization and the versatility and the undemanding nature of containers makes them viable candidates for achieving a one-to-one client-server architecture and the associated security benefits. Our team\u27s goal for this Major-Qualifying Project is to host WPI\u27s InstructAssist class management software using this model. Thus, each user session will be have its own instance of the web server in a container, preventing denial of service attacks by attacking a single point of failure and data theft attacks by employing a Query Restrictor