Context Sensitive Access Control Model TI for Business Processes

Kontrola pristupa odnosno autorizacija, u širem smislu, razmatra na koji način korisnici mogu pristupiti resursima računarskog sistema i na koji način ih koristiti. Ova disertacija se bavi problemima kontrole pristupa u poslovnim sistemima. Tema disertacije je formalna specifkacija modela kontekstno zavisne kontrole pristupa u poslovnim sistemima koji je baziran na RBAC modelu kontrole pristupa. Uvođenjem kontekstno zavisne kontrole pristupa omogućeno je defnisanje složenijih prava pristupa koje u postojećim modelima kontrole pristupa za poslovne sisteme nije bilo moguće realizovati ili bi njihova realizacija bila komplikovana. Dati model primenljiv je u različitim poslovnim sistemima, a podržava defnisanje prava pristupa kako za jednostavne tako i za slo·zene poslovne tokove. Sistem je verifkovan na dva realna poslovna procesa pomoću razvijenog prototipa. Prikazana prototipska implementacija koja ispunjava ciljeve u pogledu funkcionalnosti postavljene pred sistem predstavlja potvrdu praktične vrednosti predloženog modela.Access control is concerned with the way in which users can access to resources in the computer system. This dissertation focuses on problems of access control for business processes. The subject of the dissertation is a formal specification of the RBAC-based context sensitive access control model for business processes. By using a context-sensitive access control it is possible to define more complex access control policies whose implementation in existing access control models for business processes is not possible or is very complicated. The given model is applicable in diferent business systems, and supports the definition of access control policies for both simple and complex business processes. The model's prototype is verified by two case studies on real business processes. The presented prototype implementation represents a proof of the proposed model's practical value

Implementing the CoSaWoE models in a commercial workflow product

Workflow systems have gained popularity not only as a research topic, but also as a key component of Enterprize Resource Planning packages and e- business. Comprehensive workflow products that automate intra- as well inter-organizational information flow are now available for commercial use. Standardization efforts have centered mostly around the interoperability of these systems, however a standard access control model have yet to be adopted. The research community has developed several models for access control to be included as part of workflow functionality. Commercial systems, however, are still implementing access control functionality in a proprietary manner. This dissertation investigates whether a comprehensive model for gain- ing context-sensitive access control, namely CoSAWoE, can be purposefully implemented in a commercial workflow product. Using methods such as an exploratory prototype, various aspects of the model was implemented to gain an understanding of the di±culties developers face when attempting to map the model to existing proprietary software. Oracle Workflow was chosen as an example of a commercial workflow product. An investigtion of the features of this product, together with the prototype, revealed the ability to affect access control in a similar manner to the model: by specifying access control constraints during administration and design, and then enforcing those constraints dynamically during run-time. However, only certain components within these two aspects of the model directly effected the commercial workflow product. It was argued that the first two requirements of context-sensitive access control, order of events and strict least privilege, addressed by the object design, role engineering and session control components of the model, can be simulated if such capabilities are not pertinently available as part of the product. As such, guidelines were provided for how this can be achieved in Oracle Workflow. However, most of the implementation effort focussed on the last requirement of context-sensitive access control, namely separation of duties. The CoSAWoE model proposes SoD administration steps that includes expressing various business rules through a set of conflicting entities which are maintained outside the scope of the workflow system. This component was implemented easily enough through tables which were created with a relational database. Evaluating these conflicts during run-time to control worklist generation proved more di±cult. First, a thorough understanding of the way in which workflow history is maintained was necessary. A re-usable function was developed to prune user lists according to user involvement in previous tasks in the workflow and the conflicts specified for those users and tasks. However, due to the lack of a central access control service, this re- usable function must be included in the appropriate places in the workflow process model. Furthermore, the dissertation utilized a practical example to develop a prototype. This prototype served a dual purpose: firstly, to aid the author's understanding of the features and principles involved, and secondly, to illustrate and explore the implementation of the model as described in the previous paragraphs. In conclusion the dissertation summarized the CoSAWoE model's compo- nents which were found to be product agnostic, directly or indirectly imple- mentable, or not implemented in the chosen workflow product. The lessons learnt and issues surrounding the implementation effort were also discussed before further research in terms of XML documents as data containers for the workfow process were suggested

Constraining application behaviour by generating languages

Writing a platform for reactive applications which enforces operational constraints is difficult, and has been approached in various ways. In this experience report, we detail an approach using an embedded DSL which can be used to specify the structure and permissions of a program in a given application domain. Once the developer has specified which components an application will consist of, and which permissions each one needs, the specification itself evaluates to a new, tailored, language. The final implementation of the application is then written in this specialised environment where precisely the API calls associated with the permissions which have been granted, are made available. Our prototype platform targets the domain of mobile computing, and is implemented using Racket. It demonstrates resource access control (e.g., camera, address book, etc.) and tries to prevent leaking of private data. Racket is shown to be an extremely effective platform for designing new programming languages and their run-time libraries. We demonstrate that this approach allows reuse of an inter-component communication layer, is convenient for the application developer because it provides high-level building blocks to structure the application, and provides increased control to the platform owner, preventing certain classes of errors by the developer.Comment: 8 pages, 8th European Lisp Symposiu

Policy-agnostic programming on the client-side

Browser security has become a major concern especially due to web pages becoming more complex. These web applications handle a lot of information, including sensitive data that may be vulnerable to attacks like data exfiltration, cross-site scripting (XSS), etc. Most modern browsers have security mechanisms in place to prevent such attacks but they still fall short in preventing more advanced attacks like evolved variants of data exfiltration. Moreover, there is no standard that is followed to implement security into the browser. A lot of research has been done in the field of information flow security that could prove to be helpful in solving the problem of securing the client-side. Policy- agnostic programming is a programming paradigm that aims to make implementation of information flow security in real world systems more flexible. In this paper, we explore the use of policy-agnostic programming on the client-side and how it will help prevent common client-side attacks. We verify our results through a client-side salary management application. We show a possible attack and how our solution would prevent such an attack

A Distributed Context-Aware Trust Management Architecture

The realization of a pervasive context-aware service platform imposes new challenges for the security and privacy aspects of the system in relation to traditional service platforms. One important aspect is related with the management of trust relationships, which is especially hard in a pervasive environment because users are supposed to interact with entities unknown before hand in an ad-hoc and dynamic manner. Current trust management solutions do not adapt nor scale well in this dynamic service provisioning scenario because they require previously defined trust relationships in order to operate. The objective of this thesis is to design, prototype and validate a context-aware distributed trust management architecture in order to address: (a) the lack of integration between available trust solutions and security and privacy management languages, and (b) the dynamic characteristics of a context-aware service platform

The Transitivity of Trust Problem in the Interaction of Android Applications

Mobile phones have developed into complex platforms with large numbers of installed applications and a wide range of sensitive data. Application security policies limit the permissions of each installed application. As applications may interact, restricting single applications may create a false sense of security for the end users while data may still leave the mobile phone through other applications. Instead, the information flow needs to be policed for the composite system of applications in a transparent and usable manner. In this paper, we propose to employ static analysis based on the software architecture and focused data flow analysis to scalably detect information flows between components. Specifically, we aim to reveal transitivity of trust problems in multi-component mobile platforms. We demonstrate the feasibility of our approach with Android applications, although the generalization of the analysis to similar composition-based architectures, such as Service-oriented Architecture, can also be explored in the future