Nils Ulltveit-Moe

Decision-cache based XACML authorisation and anonymisation for XML documents

This paper describes a decision cache for the eXtensible Access Control Markup Language (XACML) that supports fine-grained authorisation and anonymisation of XML based messages and documents down to XML attribute and element level. The decision cache is implemented as an XACML obligation service, where a specification of the XML elements to be authorised and anonymised is sent to the Policy Enforcement Point (PEP) during initial authorisation. Further authorisation of individual XML elements according to the authorisation specification is then performed on all matching XML resources, and decisions are stored in the decision cache. This makes it possible to cache fine-grained XACML authorisation and anonymisation decisions, which reduces the authorisation load on the Policy Decision Point (PDP). The theoretical solution is related to a practical case study consisting of a privacy-enhanced intrusion detection system that needs to perform anonymisation of Intrusion Detection Message Exchange Format (IDMEF) XML messages before they are sent to a security operations centre that operates in privacy-preserving mode. The solution increases the scalability of XACML based authorisation significantly, and may be instrumental in implementing federated authorisation and anonymisation based on XACML in several areas, including intrusion detection systems, web services, content management systems and GRID based authentication and authorisation.

Location-Aware Mobile Intrusion Detection with Enhanced Privacy in a 5G Context

The paper proposes a location-aware mobile Intrusion Prevention System (mIPS) architecture with enhanced privacy that is integrated in Managed Security Service (MSS). The solution is envisaged in a future fifth generation telecommunications (5G) context with increased but varying bandwidth, a virtualised execution environment and infrastructure that allows threads, processes, virtual machines and storage to be migrated to cloud computing services on demand, to dynamically scale performance and save power. 5G mobile devices will be attractive targets for malicious software, and this threat will in some cases change with location. Mobile devices will store more sensitive information and will also be used to a larger extent for sensitive transactions than they typically do today. In addition, a distributed execution environment in itself gives raise to some new security challenges. In order to handle these security challenges, we have proposed the location-aware mIPS architecture, which benefits from a distributed execution environment where processor intensive services can be outsourced to Cloud hosting providers. The mIPS supports querying location threat profiles in a privacy-preserving way, and ensures that mIPS alerts sent to the the first-line MSS are anonymised. We finally perform an analysis of potential strengths and weaknesses of the proposed approach.

A proposed architecture for large scale web accessibility assessment

This paper outlines the architecture of a system designed to demonstrate large scale web accessibility assessment developed in a European research project. The system consists of a set of integrated software components designed to automatically evaluate accessibility metrics for a large number of websites and present results in a common report. The system architecture is designed to be maintainable, scalable, and extensible in order to facilitate further development of the tool. To meet these design criteria within a limited set of resources, an Open Source approach is adopted both for selecting, designing and developing the software

Mobile Security with Location-Aware Role-Based Access Control

This paper describes how location-aware Role-Based Access Control (RBAC) can be implemented on top of the Geographically eXtensible Access Control Markup Language (GeoXACML). It furthermore sketches how spatial separation of duty constraints (both static and dynamic) can be implemented using GeoXACML on top of the XACML RBAC profile. The solution uses physical addressing of geographical locations which facilitates easy deployment of authorisation profiles to the mobile device. Location-aware RBAC can be used to implement location dependent access control and also other security enhancing solutions on mobile devices, like location dependent device locking, firewall, intrusion prevention or payment anti-fraud systems.

A novel policy-driven reversible anonymisation scheme for XML-based services

This paper proposes a reversible anonymisation scheme for XML messages that supports fine-grained enforcement of XACML-based privacy policies. Reversible anonymisation means that information in XML messages is anonymised, however the information required to reverse the anonymisation is cryptographically protected in the messages. The policy can control access down to octet ranges of individual elements or attributes in XML messages. The reversible anonymisation protocol effectively implements a multi-level privacy and security based approach, so that only authorised stakeholders can disclose confidential information up to the privacy or security level they are authorised for. The approach furthermore supports a shared secret based scheme, where stakeholders need to agree to disclose confidential information. Last, it supports time limited access to private or confidential information. This opens up for improved control of access to private or confidential information in XML messages used by a service oriented architecture. The solution provides horizontally scalable confidentiality protection for certain types of big data applications, like XML databases, secure logging and data retention repositories.

Enforcing mobile security with location-aware role-based access control

This paper describes how location-aware role-based access control RBAC can be implemented on top of the Geospatial eXtensible Access Control Markup Language GeoXACML. It furthermore sketches how spatial separation of duty constraints both static and dynamic can be implemented using GeoXACML on top of the XACML RBAC profile. The solution uses physical addressing of geographical locations, which facilitates easy deployment of authorisation profiles to the mobile device. Location-aware RBAC can be used to implement location-dependent access control and also other security enhancing solutions on mobile devices, such as location-dependent device locking, firewall, intrusion prevention or payment anti-fraud systems. The system has been implemented and tested, both to verify the server capacity and also the client capacity running on a mobile device. Copyright

A scratch-based graphical policy editor for XACML

This paper proposes a policy-maker-friendly editor for the extensible Access Control Markup Language (XACML) based on the programming language Scratch. Scratch is a blocks-based programming language designed for teaching children programming, which allows users to build programs like a puzzle. We take this concept one step further with an XACML policy editor based on the graphic programming elements of Scratch implemented in Smalltalk. This allows for aiding the user on how to build policies by grouping blocks and operators that fit together and also indicating which blocks that will stick together. It simplifies building the XACML policies while still having an XACML “feel” of the graphic policies.

Domestic demand predictions considering influence of external environmental parameters

A precise prediction of domestic demand is very important for establishing home energy management system and preventing the damage caused by overloading. In this work, active and reactive power consumption prediction model based on historical power usage data and external environment parameter data (temperature and solar radiation) is presented for a typical Southern Norwegian house. In the presented model, a neural network is adopted as a main prediction technique and historical domestic load data of around 2 years are utilized for training and testing purpose. Temperature and global irradiation (which illustrates the solar radiation level quantitatively) are employed as external parameters. From the results, the efficiency of predictions are evaluated and compared. It can be observed from the numerical results that predictions using historical power data together with external data perform better than the case where only power usage data are adopted.

Two tiered privacy enhanced intrusion detection system architecture

The paper describes an architecture for privacy-enhanced intrusion detection systems, that separates privacy-invasive and privacy-preserving operations. This can be useful in cases where less sensitive network monitoring is outsourced to a third party and more sensitive network monitoring operations and data forensics are performed in-house or by law enforcement agencies.

PRIvacy LEakage Methodology (PRILE) for IDS Rules

This paper introduces a methodology for evaluating PRIvacy LEakage in signature-based Network Intrusion Detection System (IDS) rules. IDS rules that expose more data than a given percentage of all data sessions are defined as privacy leaking. Furthermore, it analyses the IDS rule attack specific pattern size required in order to keep the privacy leakage below a given threshold, presuming that occurrence frequencies of the attack pattern in normal text are known. We have applied the methodology on the network intrusion detection system Snort’s rule set. The evaluation confirms that Snort in its default configuration aims at not being excessively privacy invasive. However we have identified some types of rules rules with poor or missing ability to distinguish attack traffic from normal traffic.