154 research outputs found
Performance study of a COTS Distributed DBMS adapted for multilevel security
Multilevel secure database management system (MLS/DBMS) products
no longer enjoy direct commercial-off-the-shelf (COTS) support.
Meanwhile, existing users of these MLS/DBMS products continue to
rely on them to satisfy their multilevel security requirements.
This calls for a new approach to developing MLS/DBMS systems, one
that relies on adapting the features of existing COTS database
products rather than depending on the traditional custom design
products to provide continuing MLS support.
We advocate fragmentation as a good basis for implementing
multilevel security in the new approach because it is well
supported in some current COTS database management systems. We
implemented a prototype that utilises the inherent advantages of
the distribution scheme in distributed databases for controlling
access to single-level fragments; this is achieved by augmenting
the distribution module of the host distributed DBMS with MLS code
such that the clearance of the user making a request is always
compared to the classification of the node containing the
fragments referenced; requests to unauthorised nodes are simply
dropped.
The prototype we implemented was used to instrument a series of
experiments to determine the relative performance of the tuple,
attribute, and element level fragmentation schemes. Our
experiments measured the impact on the front-end and the network
when various properties of each scheme, such as the number of
tuples, attributes, security levels, and the page size, were
varied for a Selection and Join query. We were particularly
interested in the relationship between performance degradation and
changes in the quantity of these properties. The performance of
each scheme was measured in terms of its response time.
The response times for the element level fragmentation scheme
increased as the numbers of tuples, attributes, security levels,
and the page size were increased, more significantly so than when
the number of tuples and attributes were increased. The response
times for the attribute level fragmentation scheme was the
fastest, suggesting that the performance of the attribute level
scheme is superior to the tuple and element level fragmentation
schemes. In the context of assurance, this research has also shown
that the distribution of fragments based on security level is a
more natural approach to implementing security in MLS/DBMS
systems, because a multilevel database is analogous to a
distributed database based on security level.
Overall, our study finds that the attribute level fragmentation
scheme demonstrates better performance than the tuple and element
level schemes. The response times (and hence the performance) of
the element level fragmentation scheme exhibited the worst
performance degradation compared to the tuple and attribute level
schemes
Establishing mandatory access control on Android OS
Common characteristic of all mobile operating systems for smart devices is an extensive middleware that provides a feature-rich API for the onboard sensors and userâs data (e.g., contacts). To effectively protect the deviceâs integrity, the userâs privacy, and to ensure non-interference between mutually distrusting apps, it is imperative that the middleware enforces rigid security and privacy policies.
This thesis presents a line of work that integrates mandatory access control (MAC) mechanisms into the middleware of the popular, open source Android OS. While our early work established a basic understanding for the integration of enforcement hooks and targeted very specific use-cases, such as multi-persona phones, our most recent works adopt important lessons learned and design patterns from established MAC architectures on commodity systems and intertwine them with the particular security requirements of mobile OS architectures like Android. Our most recent work also complemented the Android IPC mechanism with provisioning of better provenance information on the origins of IPC communication. Such information is a crucial building block for any access control mechanism on Android. Lastly, this dissertation outlines further directions of ongoing and future research on access control on modern mobile operating systems.Gemeinsame Charakteristik aller modernen mobilen Betriebssysteme fĂŒr sog. âsmart devicesâ ist eine umfangreiche Diensteschicht, die funktionsreiche Programmierschnittstellen zu der GerĂ€tehardware sowie den Endbenutzerdaten (z.B. Adressbuch) bereitstellt. Um die SystemintegritĂ€t, die PrivatsphĂ€re des Endbenutzers, sowie die Abgrenzung sich gegenseitig nicht vertrauender Apps effektiv zu gewĂ€hrleisten, ist es unabdingbar, dass diese Diensteschichten rigide Sicherheitspolitiken umsetzen.
Diese Dissertation prĂ€sentiert mehrere Forschungsarbeiten, die âMandatory Access Controlâ (MAC) in die Diensteschicht des weit verbreiteten Android Betriebssystems integrieren. Die ersten dieser Arbeiten schufen ein grundlegendes VerstĂ€ndnis fĂŒr die Integration von Zugriffsmechanismen in das Android Betriebssystem und waren auf sehr spezielle Anwendungsszenarien ausgerichtet. Neuere Arbeiten haben hingegen wichtige Erkenntnisse und Designprinzipien etablierter MAC Architekturen auf herkömmlichen Betriebssystemen fĂŒr Android adaptiert und mit den speziellen Sicherheitsanforderungen mobiler Systeme verflochten. Die letzte Arbeit in dieser Reihe hat zudem Androids IPC Mechanismus untersucht und dahingehend ergĂ€nzt, dass er bessere Informationen ĂŒber den Ursprung von IPC Nachrichten bereitstellt. Diese Informationen sind fundamental fĂŒr jedwede Art von Zugriffskontrolle auf Android. Zuletzt diskutiert diese Dissertation aktuelle und zukĂŒnftige Forschungsthemen fĂŒr Zugriffskontrollen auf modernen, mobilen EndgerĂ€ten
A DISTRIBUTED APPROACH TO PRIVACY ON THE CLOUD
The increasing adoption of Cloud-based data processing and storage poses a number of privacy issues. Users wish to preserve full control over their sensitive data and cannot accept it to be fully accessible to an external storage provider. Previous research in this area was mostly addressed at techniques to protect data stored on untrusted database servers; however, I argue that the Cloud architecture presents a number of specific problems and issues. This dissertation contains a detailed analysis of open issues. To handle them, I present a novel approach where confidential data is stored in a highly distributed partitioned database, partly located on the Cloud and partly on the clients.
In my approach, data can be either private or shared; the latter is shared in a secure manner by means of simple grant-and-revoke permissions. I have developed a proof-of-concept implementation using an in\u2011memory RDBMS with row-level data encryption in order to achieve fine-grained data access control. This type of approach is rarely adopted in conventional outsourced RDBMSs because it requires several complex steps. Benchmarks of my proof-of-concept implementation show that my approach overcomes most of the problems
Decentralized information flow control for databases
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2012.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student-submitted PDF version of thesis.Includes bibliographical references (p. 177-194).Privacy and integrity concerns have been mounting in recent years as sensitive data such as medical records, social network records, and corporate and government secrets are increasingly being stored in online systems. The rate of high-profile breaches has illustrated that current techniques are inadequate for protecting sensitive information. Many of these breaches involve databases that handle information for a multitude of individuals, but databases don't provide practical tools to protect those individuals from each other, so that task is relegated to the application. This dissertation describes a system that improves security in a principled way by extending the database system and the application platform to support information flow control. Information flow control has been gaining traction as a practical way to protect information in the contexts of programming languages and operating systems. Recent research advocates the decentralized model for information flow control (DIFC), since it provides the necessary expressiveness to protect data for many individuals with varied security concerns.However, despite the fact that most applications implicated in breaches rely on relational databases, there have been no prior comprehensive attempts to extend DIFC to a database system. This dissertation introduces IFDB, which is a database management system that supports DIFC with minimal overhead. IFDB pioneers the Query by Label model, which provides applications with a simple way to delineate constraints on the confidentiality and integrity of the data they obtain from the database. This dissertation also defines new abstractions for managing information flows in a database and proposes new ways to address covert channels. Finally, the IFDB implementation and case studies with real applications demonstrate that database support for DIFC improves security, is easy for developers to use, and has good performance.by David Andrew Schultz.Ph.D
Multilevel security and concurrency control for distributed computer systems
Multilevel security deals with the problem of controlling the flow of classified information. We present multilevel information flow control mechanisms for distributed systems that allow concurrent accesses to shared data. In a distributed computing environment, the different sites communicate through message passing. Our security mechanisms check the security of information flows caused by computations within individual sites as well as ones caused by communications among the sites. The correct behavior of the security mechanisms cannot be guaranteed if the allowed concurrency is left uncontrolled in the system. We present concurrency control mechanisms for the security mechanisms. In the presence of such concurrency control mechanisms, the consistency of the security data, which the security mechanisms rely upon, is preserved. Finally, we also present schemes to increase the efficiency and the precision of the security mechanisms
âEnhanced Encryption and Fine-Grained Authorization for Database Systems
The aim of this research is to enhance fine-grained authorization and encryption
so that database systems are equipped with the controls necessary to help
enterprises adhere to zero-trust security more effectively. For fine-grained
authorization, this thesis has extended database systems with three new
concepts: Row permissions, column masks and trusted contexts. Row
permissions and column masks provide data-centric security so the security
policy cannot be bypassed as with database views, for example. They also
coexist in harmony with the rest of the database core tenets so that enterprises
are not forced to compromise neither security nor database functionality. Trusted
contexts provide applications in multitiered environments with a secure and
controlled manner to propagate user identities to the database and therefore
enable such applications to delegate the security policy to the database system
where it is enforced more effectively. Trusted contexts also protect against
application bypass so the application credentials cannot be abused to make
database changes outside the scope of the applicationâs business logic. For
encryption, this thesis has introduced a holistic database encryption solution to
address the limitations of traditional database encryption methods. It too coexists
in harmony with the rest of the database core tenets so that enterprises are not
forced to choose between security and performance as with column encryption,
for example. Lastly, row permissions, column masks, trusted contexts and holistic
database encryption have all been implemented IBM DB2, where they are relied
upon by thousands of organizations from around the world to protect critical data
and adhere to zero-trust security more effectively
EFFICIENT RUNTIME SECURITY SYSTEM FOR DECENTRALISED DISTRIBUTED SYSTEMS
Distributed systems can be defined as systems that are scattered over geographical distances and provide different activities through communication, processing, data transfer and so on. Thus, increasing the cooperation, efficiency, and reliability to deal with users and data resources jointly. For this reason, distributed systems have been shown to be a promising infrastructure for most applications in the digital world. Despite their advantages, keeping these systems secure, is a complex task because of the unconventional nature of distributed systems which can produce many security problems like phishing, denial of services or eavesdropping. Therefore, adopting security and privacy policies in distributed systems will increase the trustworthiness between the users and these systems. However, adding or updating security is considered one of the most challenging concerns and this relies on various security vulnerabilities which existing in distributed systems. The most significant one is inserting or modifying a new security concern or even removing it according to the security status which may appear at runtime. Moreover, these problems will be exacerbated when the system adopts the multi-hop concept as a way to deal with transmitting and processing information. This can pose many significant security challenges especially if dealing with decentralized distributed systems and the security must be furnished as end-to-end. Unfortunately, existing solutions are insufficient to deal with these problems like CORBA which is considered a one-to-one relationship only, or DSAW which deals with end-to-end security but without taking into account the possibility of changing information sensitivity during runtime. This thesis provides a proposed mechanism for enforcing security policies and dealing with distributed systemsâ security weakness in term of the software perspective. The proposed solution utilised Aspect-Oriented Programming (AOP), to address security concerns during compilation and running time. The proposed solution is based on a decentralized distributed system that adopts the multi-hop concept to deal with different requested tasks. The proposed system focused on how to achieve high accuracy, data integrity and high efficiency of the distributed system in real time. This is done through modularising the most efficient security solutions, Access Control and Cryptography, by using Aspect-Oriented Programming language. The experimentsâ results show the proposed solution overcomes the shortage of the existing solutions by fully integrating with the decentralized distributed system to achieve dynamic, high cooperation, high performance and end-to-end holistic security
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