waashk/dblp huggingface dataset:
secret handshakes from pairing-based key agreements. consider a cia agent who wants to authenticate herselfto a server, but does not want to reveal her cia credentialsunless the server is a genuine cia outlet. consider also thatthe cia server does not want to reveal its cia credentialsto anyone but cia agents - not even to other cia servers.in this paper we first show how pairing-based cryptographycan be used to implement such secret handshakes.we then propose a formal definition for secure secret handshakes,and prove that our pairing-based schemes are secureunder the bilinear diffie-hellman assumption. ourprotocols support role-based group membership authentication,traceability, indistinguishability to eavesdroppers,unbounded collusion resistance, and forward repudiability.our secret-handshake scheme can be implemented as atls cipher suite. we report on the performance of our preliminaryjava implementation.
constrained delegation. sometimes it is useful to be able to separate between the management of a set of resources, and the access to the resources themselves.current accounts of delegation do not allow such distinctions to be easily made, however.we introduce a new model for delegation to address this issue. the approach is based on the idea of controlling the possible shapes of delegation chains.we use constraints to restrict the capabilities at each step of delegation.constraints may re?ect e.g.group memberships, timing constraints, or dependencies on external data.regular expressions are used to describe chained constraints.we present a number of example delegation structures, based on a scenario of collaborating organisations.
the many-time pad: theme and variations. the man-time pad is a method of subverting thesecurity controls of a system to obtain data that is notdirectly accessible(e.g., because the data is confidential,classified, or otherwise deemed sensitive). it is theantithesis of the one-time pad, the only theoreticallyunbreakable cipher, in two respects: 1) whereas theone-time pad is a method of protection,the many-timepad is a method of attack; and 2) whereas the one-timepad is used just once, the many-time pad is reusable.a1so, whereas the interpretation of "pad" m the one-timepad comes from a "pad of paper", its interpretation in the many-time pad comes from "stuffing".what makes the many-time pad attack interesting isthat it arises in three different contexts: cryptographicsystems, where digital signatures can be forged ormessages decrypted; statistical databases, wheretrackers can be used to obtain confidential data; andprogramming systems, where trojan horses can beplanted in programs to leak sensitive input data, weshall first describe the basic structure of the attack andcountermeasures for foiling it. we shall then show howthese three seemingly unrelated security threats arevariations of a common theme.
an intrusion-detection model. a model of a real-time intrusion-detection expert system capable of detecting break-ins, penetrations, and other forms of computer abuse is described. the model is based on the hypothesis that security violations can be detected by monitoring a system's audit records for abnormal patterns of system usage. the model includes profiles for representing the behavior of subjects with respect to objects in terms of metrics and statistical models, and rules for acquiring knowledge about this behavior from audit records and for detecting anomalous behavior. the model is independent of any particular system, application environment, system vulnerability, or type of intrusion, thereby providing a framework for a general-purpose intrusion-detection expert system.
firmato: a novel firewall management toolkit. in recent years packet-filtering firewalls have seen some impressive technological advances (e.g., stateful inspection, transparency, performance, etc.) and wide-spread deployment. in contrast, firewall and security <i>management</i> technology is lacking. in this paper we present <i>firmato</i>, a firewall management toolkit, with the following distinguishing properties and components: (1) an entity-relationship model containing, in a unified form, global knowledge of the security policy and of the network topology; (2) a model definition language, which we use as an interface to define an instance of the entity-relationship model; (3) a model compiler, translating the global knowledge of the model into firewall-specific configuration files; and (4) a graphical firewall rule illustrator. we implemented a prototype of our toolkit to work with several commercially available firewall products. this prototype was used to control an operational firewall for several months. we believe that our approach is an important step toward streamlining the process of configuring and managing firewalls, especially in complex, multi-firewall installations.
privacy and contextual integrity: framework and applications. contextual integrity is a conceptual framework for understanding privacy expectations and their implications developed in the literature on law, public policy, and political philosophy. we formalize some aspects of contextual integrity in a logical framework for expressing and reasoning about norms of transmission of personal information. in comparison with access control and privacy policy frameworks such as rbac, epal, and p3p, these norms focus on who personal information is about, how it is transmitted, and past and future actions by both the subject and the users of the information. norms can be positive or negative depending on whether they refer to actions that are allowed or disallowed. our model is expressive enough to capture naturally many notions of privacy found in legislation, including those found in hipaa, coppa, and glba. a number of important problems regarding compliance with privacy norms, future requirements associated with specific actions, and relations between policies and legal standards reduce to standard decision procedures for temporal logic.
deriving an information flow checker and certifying compiler for java. language-based security provides a means to enforce endto- end confidentiality and integrity policies inmobile code scenarios, and is increasingly being contemplated by the smartcard and mobile phone industry as a solution to enforce information flow and resource control policies. two threads of work have emerged in research on languagebased security: work that focuses on enforcing security policies for source code, which is tailored towards developers that want to increase confidence in their applications, and work that focuses on efficiently verifying similar policies for bytecode, which is tailored to code consumers that want to protect themselves against hostile applications. these lines of work serve different purposes - and thus have been developed independently but connecting them is a key step towards the deployment of language-based security in practical applications. this paper introduces a systematic technique to connect source code and bytecode security type systems. the technique is applied to an information flow type system for a fragment of java with exceptions, thus confronting challenges in both control and data flow tracking.
distributed proving in access-control systems. we present a distributed algorithm for assembling a proof that a request satisfies an access-control policy expressed in a formal logic, in the tradition of lampson et al. we show analytically that our distributed proof-generation algorithm succeeds in assembling a proof whenever a centralized prover utilizing remote certificate retrieval would do so. in addition, we show empirically that our algorithm outperforms centralized approaches in various measures of performance and usability, notably the number of remote requests and the number of user interruptions. we show that when combined with additional optimizations including caching and automatic tactic generation, which we introduce here, our algorithm retains its advantage, while achieving practical performance. finally, we briefly describe the utilization of these algorithms as the basis for an access-control framework being deployed for use at our institution.
secure computer systems: a retrospective. eight years after the completion of the "securecomputer systems" series, basic questions about thatwork are being raised. is the model useful? is itoverly restrictive? are further modeling effortsnecessary to address current problems? this paperaddresses those questions in a personal view of thedevelopment and the utility of the "secure computersystems" security model. the acm portal is published by the association for computing machinery. copyright © 2010 acm, inc. terms of usage privacy policy code of ethics contact us useful downloads: adobe acrobat quicktime windows media player real player
an immunological approach to change detection: algorithms, analysis and implications. 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 provides a basis for assessing the practicality of the algorithms in specific settings, and some of the implications are discussed.
supporting multiple access control policies in database systems. elisa bertino, sushil jajodia, and pierangela samarati 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.
random key predistribution schemes for sensor networks. key establishment in sensor networks is a challengingproblem because asymmetric key cryptosystems are unsuitablefor use in resource constrained sensor nodes, and alsobecause the nodes could be physically compromised by anadversary. we present three new mechanisms for key establishmentusing the framework of pre-distributing a randomset of keys to each node. first, in the q-compositekeys scheme, we trade off the unlikeliness of a large-scalenetwork attack in order to significantly strengthen randomkey predistribution's strength against smaller-scale attacks.second, in the multipath-reinforcement scheme, we showhow to strengthen the security between any two nodes byleveraging the security of other links. finally, we presentthe random-pairwise keys scheme, which perfectly preservesthe secrecy of the rest of the network when any nodeis captured, and also enables node-to-node authenticationand quorum-based revocation.
logic induction of valid behavior specifications for intrusion detection. this paper introduces an automated technique for constructing valid behavior specifications of programs (at the system call level) that are independent of system vulnerabilities and are highly effective in identifying intrusions. the technique employs a machine learning method, inductive logic programming (ilp), for synthesizing first order logic formulas that describe the valid operations of a program from the normal runs of the program. ilp, backed by theories and techniques extended from computational logic, allows the use of complex domain-specific background knowledge in the learning process to produce sound and consistent knowledge. a specification induction engine has been developed by extending an existing ilp tool and has been used to construct specifications for several (>10) privileged programs in unix. coupling with rich background knowledge in systems and security, the prototype induction engine generates human understandable and analyzable specifications that are as good as those specified by a human. preliminary experiments with existing attacks show that the generated specifications are highly effective in detecting attacks that subvert privileged programs to gain unauthorized accesses to resources.
new constructions and practical applications for private stream searching (extended abstract). a system for private stream searching allows a client to retrieve documents matching some search criteria from a remote server while the server evaluating the request remains provably oblivious to the search criteria. in this extended abstract, we give a high level outline of a new scheme for this problem and an experimental analysis of its scalability. the new scheme is highly efficient in practice. we demonstrate the practical applicability of the scheme by considering its performance in the demanding scenario of providing a privacy preserving version of the google news alerts service.
dataflow anomaly detection. beginning with the work of forrest et al, several researchers have developed intrusion detection techniques based on modeling program behaviors in terms of system calls. a weakness of these techniques is that they focus on control flows involving system calls, but not their arguments. this weakness makes them susceptible to several classes of attacks, including attacks on security-critical data, race-condition and symbolic link attacks, and mimicry attacks. to address this weakness, we develop a new approach for learning dataflow behaviors of programs. the novelty in our approach, as compared to previous system-call argument learning techniques, is that it learns temporal properties involving the arguments of different system calls, thus capturing the flow of security-sensitive data through the program. an interesting aspect of our technique is that it can be uniformly layered on top of most existing control-flow models, and can leverage control-flow contexts to significantly increase the precision of dataflows captured by the model. this contrasts with previous system-call argument learning techniques that did not leverage control-flow information, and moreover, were focused on learning statistical properties of individual system call arguments. through experiments, we show that temporal properties enable detection of many attacks that aren't detected by previous approaches. moreover, they support formal reasoning about security assurances that can be provided when a program follows its dataflow behavior model, e.g., tar would read only files located within a directory specified as a command-line argument.
an mbone proxy for an application gateway firewall. the internet's multicast backbone (mbone) holds great potential for many organizations because it supports low-cost audio and video conferencing and carries live broadcasts of an increasing number of public interest events. mbone conferences are transmitted via unauthenticated multicast datagrams, which unfortunately convey significant security vulnerabilities to any system that receives them. for this reason, most application gateway firewalls block mbone datagrams sent from the internet and prevent them from reaching hosts on internal networks.this paper describes the design and rationale for a new set of facilities for the tis internet firewall toolkit (fwtk). these facilities, which are fully implemented, significantly reduce the security risks of observing or participating in mbone conferences. they impose no functional constraints on mbone applications and are transparent to users. configuration options that support tradeoffs among security, performance, and ease of use are discussed.
the final nail in wep's coffin. the 802.11 encryption standard wired equivalent privacy (wep) is still widely used today despite the numerous discussions on its insecurity. in this paper, we present a novel vulnerability which allows an attacker to send arbitrary data on a wep network after having eavesdropped a single data packet. furthermore, we present techniques for real-time decryption of data packets, which may be used under common circumstances. vendor produced mitigation techniques which cause frequent wep re-keying prevent traditional attacks, whereas our attack remains effective even in such scenarios. we implemented a fully automatic version of this attack which demonstrates its practicality and feasibility in real networks. as even rapidly re-keyed networks can be quickly compromised, we believe wep must now be abandoned rather than patched yet again.
intrusion-tolerant enclaves. despite our best efforts, any sufficiently complex computer system hasvulnerabilities. it is safe to assume that such vulnerabilities can beexploited by attackers who will be able to penetrate the system.intrusion tolerance attempts to maintain acceptable service despitesuch intrusions. this paper presents an application ofintrusion-tolerance concepts to enclaves, a software infrastructurefor supporting secure group applications. intrusion tolerance isachieved via a combination of byzantine fault-tolerant protocols andsecret sharing techniques.
some weaknesses of the tcb model. this paper summarizes the affirmative argument supporting the proposition that "the concept of the trusted computing base (tcb) as a basis for constructing systems to meet security requirements is fundamentally flawed and should no longer be used to justify system security architectures".
irm enforcement of java stack inspection. two implementations are given for java''s stack-inspection access-control policy. each implementation is obtained by generating an inlined reference monitor (irm) for a different formulation of the policy. performance of the implementations is evaluated, and one is found to be competitive with java''s less-flexible, jvm-resident implementation. the exercise illustrates the power of the irm approach for enforcing security policies.
a computationally sound mechanized prover for security protocols. we present a new mechanized prover for secrecy properties of cryptographic protocols. in contrast to most previous provers, our tool does not rely on the dolev-yao model, but on the computational model. it produces proofs presented as sequences of games; these games are formalized in a probabilistic polynomial-time process calculus. our tool provides a generic method for specifying security properties of the cryptographic primitives, which can handle sharedand public-key encryption, signatures, message authentication codes, and hash functions. our tool produces proofs valid for a number of sessions polynomial in the security parameter, in the presence of an active adversary. we have implemented our tool and tested it on a number of examples of protocols from the literature.
decentralized trust management. 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. we present a comprehensive approach to trust management, based on a simple language for specifying trusted actions and trust relationships. we also describe a prototype implementation of a "trust management system," called policymaker, that can facilitate the development of security features in a wide range of network services. this paper was presented at the ieee symposium on security and privacy, oakland ca, may 1996.
siren: catching evasive malware (short paper). with the growing popularity of anomaly detection systems, which is due partly to the rise in zero-day attacks, a new class of threats have evolved where the attacker mimics legitimate activity to blend in and avoid detection. we propose a new system called siren that injects crafted human input alongside legitimate user activity to thwart these mimicry attacks. the crafted input is specially designed to trigger a known sequence of network requests, which siren compares to the actual traffic. it then flags unexpected messages as malicious. using this method, we were able to detect ten spyware programs that we tested, many of which attempt to blend in with user activity. this paper presents the design, implementation, and evaluation of the siren activity injection system, as well as a discussion of its potential limitations.
the channel assignment problem. an optimization problem exists in the context oflocal area network security. the network provides anumber of physical or logical "channels", each carrying aset of levels or compartments of information. a channelis accessible to users cleared for all the levels it carries.the problem is to assign the set of levels to be carried byeach channel so as to minimize the total number ofchannels, under the constraint that each pair of userswith a level in common can communicate over somechannel. this problem was found to be equivalent to aknown np-complete problem, the set basis problem.themain result is an approximatealgorithm that runs inpolynomial time and finds one solution. it has succeededin finding an optimal solution in all of the test casessmall enough to confirm the optimality independently.
anomaly detection using call stack information. the call stack of a program execution can be a very goodinformation source for intrusion detection. there is no priorwork on dynamically extracting information from call stackand effectively using it to detect exploits. in this paper, wepropose a new method to do anomaly detection using callstack information. the basic idea is to extract return addressesfrom the call stack, and generate abstract executionpath between two program execution points. experimentsshow that our method can detect some attacks thatcannot be detected by other approaches, while its convergenceand false positive performance is comparable to orbetter than the other approaches. we compare our methodwith other approaches by analyzing their underlying principlesand thus achieve a better characterization of theirperformance, in particular, on what and why attacks will bemissed by the various approaches.
a trend analysis of exploitations. abstract: we have conducted an empirical study of a number of computer security exploits and determined that the rates at which incidents involving the exploit are reported to the cert can be modeled using a common mathematical framework. data associated with three significant exploits involving vulnerabilities in phf, imap, and bind can all be modeled using the formula c = i + s x vm where c is the cumulative count of reported incidents, m is the time since the start of the exploit cycle, and i and s are the regression coefficients determined by analysis of the incident report data. further analysis of two additional exploits involving vulnerabilities in mountd and statd confirm the model. we believe that the models will aid in predicting the severity of subsequent vulnerability exploitations, based on the rate of early incident reports.