By Topic

Security and Privacy, 1996. Proceedings., 1996 IEEE Symposium on

Date 6-8 May 1996

Filter Results

Displaying Results 1 - 23 of 23
  • Proceedings 1996 IEEE Symposium on Security and Privacy

    Save to Project icon | Request Permissions | PDF file iconPDF (228 KB)  
    Freely Available from IEEE
  • Index of authors

    Save to Project icon | Request Permissions | PDF file iconPDF (35 KB)  
    Freely Available from IEEE
  • Security properties and CSP

    Page(s): 174 - 187
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1104 KB)  

    Security properties such as confidentiality and authenticity may be considered in terms of the flow of messages within a network. To the extent that this characterisation is justified, the use of a process algebra such as Communicating Sequential Processes (CSP) seems appropriate to describe and analyse them. This paper explores ways in which security properties may be described as CSP specifications, how security mechanisms may be captured, and how particular protocols designed to provide these properties may be analysed within the CSP framework. The paper is concerned with the theoretical basis for such analysis. A sketch verification of a simple example is carried out as an illustration View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A security model of dynamic labelling providing a tiered approach to verification

    Page(s): 142 - 153
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1024 KB)  

    In the proposed mandatory access control model, arbitrary, label changing policies can be expressed. The relatively simple model can capture a wide variety of security policies, including high-water marks, downgrading, separation of duties, and Chinese Walls. The model forms the basis for a tiered approach to the formal development of secure systems, whereby security verification can be spread across what makes up the reference monitor and the security requirement specification. The advantage of this approach is that once a trusted computing base (TCB) is in place, reconfiguring it for different security requirements requires verification of just the new requirements. We illustrate the approach with a number of examples, including one policy that permits high-level subjects to make relabelling requests on low-level objects; the policy is multilevel secure View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Computer security training and education: a needs analysis

    Page(s): 26 - 27
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (208 KB)  

    This paper examines, from an employer's perspective, the kind of education and training that today's computer security practitioners need. It suggests answers to three important questions: (1) What are we educating people to do? (2) What should be included in education and training programs? (3) What can industry do to help? View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Ensuring atomicity of multilevel transactions

    Page(s): 74 - 84
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (964 KB)  

    Ensuring atomicity is a major outstanding problem with present methods of handling multilevel transactions. The chief difficulty is that a high section of a transaction may be unable to complete due to violations of the integrity constraints, and a rollback of sections can be exploited to implement a covert channel. We define a notion of semantic atomicity which guarantees that either all or none of the sections of a transaction are present in any history. The notion of correct executions in our model is based on semantic correctness-that is, maintenance of integrity constraints-rather than serializability. We give a method whereby the application developer can statically analyze the set of transactions in the application and determine if the set ensures semantic atomicity and other desirable properties View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Supporting multiple access control policies in database systems

    Page(s): 94 - 107
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1204 KB)  

    Although there are several choices of policies for protection of information, access control models have been developed for a fixed set pre-defined access control policies that are then built into the corresponding access control mechanisms. This becomes a problem, however, if the access control requirements of an application are different from the policies built into a mechanism. In most cases, the only solution is to enforce the requirements as part of the application code, but this makes verification, modification, and adequate enforcement of these policies impossible. In this paper, we propose a flexible authorization mechanism that can support different security policies. The mechanism enforces a general authorization model onto which multiple access control policies can be mapped. The model permits negative and positive authorizations, authorizations that must be strongly obeyed and authorizations that allow for exceptions, and enforces ownership together with delegation of administrative privileges View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A communication agreement framework for access/action control

    Page(s): 154 - 163
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1200 KB)  

    We introduce a framework for access/action control which shifts the emphasis from the participants to their relationships. The framework is based on a communication model in which participants negotiate the mutually agreed-upon boundary conditions of their relationships, and create social reference points by encapsulating them in compact “communication pacts”, called “commpacts”. Commpacts are designed to provide a language enabling a social mechanism of coordinated expectation. We argue that in networked environments characterized by multiple authorities and “trusted proxies” this model can deal with the complexities of general (user- and content-dependent) distributed access/action control and provides a clear user-conceptual metaphor The framework embeds naturally into the existing legal and institutional infrastructure; it generalizes work in electronic contracting. Commpacts can be seen as a third fundamental type next to access-control lists (ACLs) and capabilities View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Secure network objects

    Page(s): 211 - 221
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (952 KB)  

    We describe the design and implementation of secure network objects, which provide security for object-oriented network communication. The design takes advantage of objects and subtyping to present a simple but expressive programming interface for security, supporting both access control lists and capabilities. The implementation of this design fits nicely within the structure of the existing network objects system; we discuss its internal components, its performance, and its use in some applications View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • What do we mean by entity authentication?

    Page(s): 46 - 54
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (832 KB)  

    The design of authentication protocols has proven to be surprisingly error-prone. We suggest that this is partly due to a language problem. The objectives of entity authentication are usually given in terms of human encounters while we actually implement message passing protocols. We propose various translations of the high-level objectives into a language appropriate for communication protocols. In addition, protocols are often specified at too low a level of abstraction. We argue that encryption should not be used as a general primitive as it does not capture the specific purpose for using a cryptographic function in a particular protocol View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A sense of self for Unix processes

    Page(s): 120 - 128
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (804 KB)  

    A method for anomaly detection is introduced in which “normal” is defined by short-range correlations in a process' system calls. Initial experiments suggest that the definition is stable during normal behaviour for standard UNIX programs. Further; it is able to detect several common intrusions involving sendmail and 1pr. This work is part of a research program aimed at building computer security systems that incorporate the mechanisms and algorithms used by natural immune systems View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Defining noninterference in the temporal logic of actions

    Page(s): 12 - 21
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1060 KB)  

    Covert channels are a critical concern for multilevel secure (MLS) systems. Due to their subtlety, it is desirable to use formal methods to analyze MLS systems for the presence of covert channels. This paper describes an approach for using Abadi & Lamport's (1993) temporal logic of actions (TLA) to specify noninterference properties. In addition to providing a more intuitive definition of noninterference than previous attempts, this approach also supports the analysis of systems that do contain covert channels to demonstrate limitations on their exploitations. In relating the definition of noninterference given in this paper to prior definitions of noninterference, this paper discusses ways in which other definitions of noninterference can be formalized in TLA, too. Finally, this paper discusses how prior work on specification refinement and composition might be applied to the noninterference problem within the framework provided by TLA View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Decentralized trust management

    Page(s): 164 - 173
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (932 KB)  

    We identify the trust management problem as a distinct and important component of security in network services. Aspects of the trust management problem include formulating security policies and security credentials, determining whether particular sets of credentials satisfy the relevant policies, and deferring trust to third parties. Existing systems that support security in networked applications, including X.509 and PGP, address only narrow subsets of the overall trust management problem and often do so in a manner that is appropriate to only one application. This paper presents a comprehensive approach to trust management, based on a simple language for specifying trusted actions and trust relationships. It also describes a prototype implementation of a new trust management system, called PolicyMaker, that will facilitate the development of security features in a wide range of network services View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • View-based access control with high assurance

    Page(s): 85 - 93
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (808 KB)  

    View-based access control enables content-based and context-based security, as opposed to the container-based security provided in operating systems. However, view-based access control in multilevel secure (MLS) databases suffers from two problems: safety and assurance. We investigate view-based access control in MLS relational databases for a large class of views expressible as project-select-join queries. We develop a polynomial-time label compilation algorithm that transforms view-level labelling to tuple-level labelling in such a way that guarantees safety and high assurance. We identify two problems related to optimal label compilation, and show that they are both NP-complete even for totally ordered security lattices of size two View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • An analysis of the timed Z-channel

    Page(s): 2 - 11
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (760 KB)  

    Our timed Z-channel (a general case of the Z-channel) appears as the basis for a large class of covert channels. Golomb (1980) analyzed the Z-channel, a memoryless channel with two input symbols and two output symbols, where one of the input symbols is transmitted with noise while the other is transmitted without noise, and the output symbol transmission times are equal. We introduce the timed Z-channel, where the output symbol transmission times are different. Specifically, we show how the timed Z-channel applies to two examples of covert timing channel scenarios: a CPU scheduler and a token ring network. We then give a detailed analysis of our timed Z-channel. We report a new result expressing the capacity of the timed Z-channel as the log of the root of a trinomial equation. This changes the capacity calculation from an optimization problem into a simpler algebraic problem and illustrates the relationship between the noise and time factors. Further, it generalizes Shannon's (1948, 1949) work on noiseless channels for this special case. We also report a new result bounding the timed Z-channel's capacity from below. Finally, we show how an interesting observation that Golomb reported for the Z-channel also holds for the timed Z-channel View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • On two proposals for on-line bankcard payments using open networks: problems and solutions

    Page(s): 201 - 210
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (976 KB)  

    Recently, two major bankcard payment instrument operators VISA and MasterCard published specifications for securing bankcard payment transactions on open networks for open scrutiny. (VISA: Secure Transaction Technology, STT; MasterCard: Secure Electronic Payment Protocol, SEPP.) Based on their success in operating the existing on-line payment systems, both proposals use advanced cryptographic technologies to supply some security services that are well-understood to be inadequate in open networks, and otherwise specify systems similar to today's private-network versions. In this paper we reason that when an open network is used for underlying electronic commerce some subtle vulnerabilities will emerge and the two specifications are seen not in anticipation of them. A number of weaknesses are found as a result of missing and misuse of security services. Missing and misused services include: authentication, nonrepudiation, integrity, and timeliness, We identify problems and devise solutions while trying to keep, the current successful working style of financial institutions being respected View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A security policy model for clinical information systems

    Page(s): 30 - 43
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1332 KB)  

    The protection of personal health information has become a live issue in a number of countries, including the USA, Canada, Britain and Germany. The debate has shown that there is widespread confusion about what should be protected, and why. Designers of military and banking systems can refer to Bell & LaPadula (1973) and Clark & Wilson (1987) respectively, but there is no comparable security policy model that spells out clear and concise access rules for clinical information systems. In this article, we present just such a model. It was commissioned by doctors and is driven by medical ethics; it is informed by the actual threats to privacy, and reflects current best clinical practice. Its effect is to restrict both the number of users who can access any record and the maximum number of records accessed by any user. This entails controlling information flows across rather than down and enforcing a strong notification property. We discuss its relationship with existing security policy models, and its possible use in other applications where information exposure must be localised; these range from private banking to the management of intelligence data View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • An immunological approach to change detection: algorithms, analysis and implications

    Page(s): 110 - 119
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (912 KB)  

    We present new results on a distributable change-detection method inspired by the natural immune system. A weakness in the original algorithm was the exponential cost of generating detectors. Two detector-generating algorithms are introduced which run in linear time. The algorithms are analyzed, heuristics are given for setting parameters based on the analysis, and the presence of holes in detector space is examined. The analysis provider a basis for assessing the practicality of the algorithms in specific settings, and some of the implications are discussed View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Cryptovirology: extortion-based security threats and countermeasures

    Page(s): 129 - 140
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1176 KB)  

    Traditionally, cryptography and its applications are defensive in nature, and provide privacy, authentication, and security to users. In this paper we present the idea of Cryptovirology which employs a twist on cryptography, showing that it can also be used offensively. By being offensive we mean that it can be used to mount extortion based attacks that cause loss of access to information, loss of confidentiality, and information leakage, tasks which cryptography typically prevents. In this paper we analyze potential threats and attacks that rogue use of cryptography can cause when combined with rogue software (viruses, Trojan horses), and demonstrate them experimentally by presenting an implementation of a cryptovirus that we have tested (we took careful precautions in the process to insure that the virus remained contained). Public-key cryptography is essential to the attacks that we demonstrate (which we call “cryptovirological attacks”). We also suggest countermeasures and mechanisms to cope with and prevent such attacks. These attacks have implications on how the use of cryptographic tools should be managed and audited in general purpose computing environments, and imply that access to cryptographic tools should be well controlled. The experimental virus demonstrates how cryptographic packages can be condensed into a small space, which may have independent applications (e.g., cryptographic module design in small mobile devices) View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Limitations on design principles for public key protocols

    Page(s): 62 - 72
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1104 KB)  

    Recent papers have taken a new look at cryptographic protocols from the perspective of proposing design principles. For years, the main approach to cryptographic protocols has been logical, and a number of papers have examined the limitations of those logics. This paper takes a similar cautionary look at the design principle approach. Limitations and exceptions are offered on some of the previously given basic design principals. The focus is primarily on public key protocols, especially on the order of signature and encryption, but other principles are discussed as well. Apparently secure protocols that fail to meet principles are presented. Also presented are new attacks on protocols as well as previously claimed attacks which are not View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Java security: from HotJava to Netscape and beyond

    Page(s): 190 - 200
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1048 KB)  

    The introduction of Java applets has taken the World Wide Web by storm. Information servers can customize the presentation of their content with server-supplied code which executes inside the Web browser. We examine the Java language and both the HotJava and Netscape browsers which support it, and find a significant number of flaws which compromise their security. These flaws arise for several reasons, including implementation errors, unintended interactions between browser features, differences between the Java language and bytecode semantics, and weaknesses in the design of the language and the bytecode format. On a deeper level, these flaws arise because of weaknesses in the design methodology used in creating Java and the browsers. In addition to the flaws, we discuss the underlying tension between the openness desired by Web application writers and the security needs of their users, and we suggest how both might be accommodated View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Run-time security evaluation (RTSE) for distributed applications

    Page(s): 222 - 232
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (984 KB)  

    Formal security specifications for a distributed application can be checked for compliance at run-time using executable security assertions. We propose the run-time security evaluation (RTSE) method which makes use of histories/traces of events, assertions and operational evaluation in the distributed environment to ensure the security specifications for the application are fulfilled at run-time. A model problem is used to aid in developing the security requirements formally View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A fair non-repudiation protocol

    Page(s): 55 - 61
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (484 KB)  

    A fair non-repudiation protocol should not give the sender of a message an advantage over the receiver, or vice versa. We present a fair non-repudiation protocol that requires a trusted third party but attempts to minimize its involvement in the execution of the protocol. We draw particular attention to the nonstandard use of encryption in our protocol and discuss some aspects of its formal verification View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.