Using a loadtime metaobject protocol to enforce access control policies upon user-level compiled code

This thesis evaluates the use of a loadtime metaobject protocol as a practical mechanism for enforcing access control policies upon applications distributed as user-level compiled code. Enforcing access control policies upon user-level compiled code is necessary because there are many situations where users are vulnerable to security breaches because they download and run potentially untrustworthy applications provided in the form of user-level compiled code. These applications might be distributed applications so access control for both local and distributed resources is required. Examples of potentially untrustworthy applications are Browser plug-ins, software patches, new applications, or Internet computing applications such as SETI@home. Even applications from trusted sources might be malicious or simply contain bugs that can be exploited by attackers so access control policies must be imposed to prevent the misuse of resources. Additionally, system administrators might wish to enforce access control policies upon these applications to ensure that users use them in accordance with local security requirements. Unfortunately, applications developed externally may not include the necessary enforcement code to allow the specification of organisation-specific access control policies. Operating system security mechanisms are too coarse-grained to enforce security policies on applications implemented as user-level code. Mechanisms that control access to both user-level and operating system-level resources are required for access control policies but operating system mechanisms only focus on controlling access to system-level objects. Conventional object-oriented software engineering can be used to use existing security architectures to enforce access control on user-level resources as well as system-resources. Common techniques are to insert enforcement within libraries or applications, use inheritance and proxies. However, these all provide a poor separation of concerns and cannot be used with compiled code. In-lined reference monitors provide a good separation of concerns and meet criteria for good security engineering. They use object code rewriting to control access to both userlevel and system-level objects by in-lining reference monitor code into user-level compiled code. However, their focus is upon replacing existing security architectures and current implementations do not address distributed access control policies. Another approach that does provide a good separation of concerns and allows reuse of existing security architectures are metaobject protocols. These allow constrained changes to be made to the semantics of code and therefore can be used to implement access control policies for both local and distributed resources. Loadtime metaobject protocols allow metaobject protocols to be used with compiled code because they rewrite base level classes and insert meta-level interceptions. However, these have not been demonstrated to meet requirements for good security engineering such as complete mediation. Also current implementations do not provide distributed access control. This thesis implements a loadtime metaobject protocol for the Java programming language. The design of the metaobject protocol specifically addresses separation of concerns, least privilege, complete mediation and economy of mechanism. The implementation of the metaobject protocol, called Kava, has been evaluated by implementing diverse security policies in two case studies involving third-party standalone and distributed applications. These case studies are used as the basis of inferences about general suitability of using loadtime reflection for enforcing access control policies upon user-level compiled code.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

CamFlow: Managed Data-sharing for Cloud Services

A model of cloud services is emerging whereby a few trusted providers manage the underlying hardware and communications whereas many companies build on this infrastructure to offer higher level, cloud-hosted PaaS services and/or SaaS applications. From the start, strong isolation between cloud tenants was seen to be of paramount importance, provided first by virtual machines (VM) and later by containers, which share the operating system (OS) kernel. Increasingly it is the case that applications also require facilities to effect isolation and protection of data managed by those applications. They also require flexible data sharing with other applications, often across the traditional cloud-isolation boundaries; for example, when government provides many related services for its citizens on a common platform. Similar considerations apply to the end-users of applications. But in particular, the incorporation of cloud services within `Internet of Things' architectures is driving the requirements for both protection and cross-application data sharing. These concerns relate to the management of data. Traditional access control is application and principal/role specific, applied at policy enforcement points, after which there is no subsequent control over where data flows; a crucial issue once data has left its owner's control by cloud-hosted applications and within cloud-services. Information Flow Control (IFC), in addition, offers system-wide, end-to-end, flow control based on the properties of the data. We discuss the potential of cloud-deployed IFC for enforcing owners' dataflow policy with regard to protection and sharing, as well as safeguarding against malicious or buggy software. In addition, the audit log associated with IFC provides transparency, giving configurable system-wide visibility over data flows. [...]Comment: 14 pages, 8 figure

A trustworthy mobile agent infrastructure for network management

Despite several advantages inherent in mobile-agent-based approaches to network management as compared to traditional SNMP-based approaches, industry is reluctant to adopt the mobile agent paradigm as a replacement for the existing manager-agent model; the management community requires an evolutionary, rather than a revolutionary, use of mobile agents. Furthermore, security for distributed management is a major concern; agent-based management systems inherit the security risks of mobile agents. We have developed a Java-based mobile agent infrastructure for network management that enables the safe integration of mobile agents with the SNMP protocol. The security of the system has been evaluated under agent to agent-platform and agent to agent attacks and has proved trustworthy in the performance of network management tasks

Dynamic deployment of context-aware access control policies for constrained security devices

Securing the access to a server, guaranteeing a certain level of protection over an encrypted communication channel, executing particular counter measures when attacks are detected are examples of security requirements. Such requirements are identi ed based on organizational purposes and expectations in terms of resource access and availability and also on system vulnerabilities and threats. All these requirements belong to the so-called security policy. Deploying the policy means enforcing, i.e., con guring, those security components and mechanisms so that the system behavior be nally the one speci ed by the policy. The deployment issue becomes more di cult as the growing organizational requirements and expectations generally leave behind the integration of new security functionalities in the information system: the information system will not always embed the necessary security functionalities for the proper deployment of contextual security requirements. To overcome this issue, our solution is based on a central entity approach which takes in charge unmanaged contextual requirements and dynamically redeploys the policy when context changes are detected by this central entity. We also present an improvement over the OrBAC (Organization-Based Access Control) model. Up to now, a controller based on a contextual OrBAC policy is passive, in the sense that it assumes policy evaluation triggered by access requests. Therefore, it does not allow reasoning about policy state evolution when actions occur. The modi cations introduced by our work overcome this limitation and provide a proactive version of the model by integrating concepts from action speci cation languages