waashk/dblp huggingface dataset:
casting out demons: sanitizing training data for anomaly sensors. the efficacy of anomaly detection (ad) sensors depends heavily on the quality of the data used to train them. artificial or contrived training data may not provide a realistic view of the deployment environment. most realistic data sets are dirty; that is, they contain a number of attacks or anomalous events. the size of these high-quality training data sets makes manual removal or labeling of attack data infeasible. as a result, sensors trained on this data can miss attacks and their variations. we propose extending the training phase of ad sensors (in a manner agnostic to the underlying ad algorithm) to include a sanitization phase. this phase generates multiple models conditioned on small slices of the training data. we use these “micro-models” to produce provisional labels for each training input, and we combine the micro-models in a voting scheme to determine which parts of the training data may represent attacks. our results suggest that this phase automatically and significantly improves the quality of unlabeled training data by making it as “attack-free” and “regular” as possible in the absence of absolute ground truth. we also show how a collaborative approach that combines models from different networks or domains can further refine the sanitization process to thwart targeted training or mimicry attacks against a single site.
robust de-anonymization of large sparse datasets. we present a new class of statistical de-anonymization attacks against high-dimensional micro-data, such as individual preferences, recommendations, transaction records and so on. our techniques are robust to perturbation in the data and tolerate some mistakes in the adversary's background knowledge. we apply our de-anonymization methodology to the netflix prize dataset, which contains anonymous movie ratings of 500,000 subscribers of netflix,the world's largest online movie rental service. we demonstrate that an adversary who knows only a little bit about an individual subscriber can easily identify this subscriber's record in the dataset. using the internet movie database as the source of background knowledge, we successfully identified the netflix records of known users, uncovering their apparent political preferences and other potentially sensitive information.
jamming-resistant key establishment using uncoordinated frequency hopping. we consider the following problem: how can two devices that do not share any secrets establish a shared secret key over a wireless radio channel in the presence of a communication jammer? an inherent challenge in solving this problem is that known anti-jamming techniques (e.g.,frequency hopping or direct-sequence spread spectrum) which should support device communication during the key establishment require that the devices share a secret spreading key (or code) prior to the start of their communication. this requirement creates a circular dependency between anti-jamming spread-spectrum communication and key establishment, which has so far not been addressed. in this work, we propose an uncoordinated frequency hopping (ufh) scheme that breaks this dependencyand enables key establishment in the presence of a communication jammer. we perform a detailed analysis of our ufh scheme and show its feasibility, both in terms of execution time and resource requirements.
efficient and robust tcp stream normalization. network intrusion detection and prevention systems are vulnerable to evasion by attackers who craft ambiguous traffic to breach the defense of such systems. a normalizer is an inline network element that thwarts evasion attempts by removing ambiguities in network traffic. a particularly challenging step in normalization is the sound detection of inconsistent tcp retransmissions, wherein an attacker sends tcp segments with different payloads for the same sequence number space to present a network monitor with ambiguous analysis. normalizers that buffer all unacknowledged data to verify the consistency of subsequent retransmissions consume inordinate amounts of memory on high-speed links. on the other hand, normalizers that buffer only the hashes of unacknowledged segments cannot verify the consistency of 20-30% of retransmissions that, according to our traces, do not align with the original transmissions. this paper presents the design of robonorm, a normalizer that buffers only the hashes of unacknowledged segments, and yet can detect all inconsistent retransmissions in any tcp byte stream. robonorm consumes 1-2 orders of magnitude less memory than normalizers that buffers all unacknowledged data, and is amenable to a high-speed implementation. robonorm is also robust to attacks that attempt to compromise its operation or exhaust its resources.
towards practical privacy for genomic computation. many basic tasks in computational biology involve operations on individual dna and protein sequences. these sequences, even when anonymized, are vulnerable to re-identification attacks and may reveal highly sensitive information about individuals. we present a relatively efficient, privacy-preserving implementation of fundamental genomic computations such as calculating the edit distance and smith-waterman similarity scores between two sequences. our techniques are cryptographically secure and significantly more practical than previous solutions. we evaluate our prototype implementation on sequences from the pfam database of protein families, and demonstrate that its performance is adequate for solving real-world sequence-alignment and related problems in a privacy-preserving manner. furthermore, our techniques have applications beyond computational biology. they can be used to obtain efficient, privacy-preserving implementations for many dynamic programming algorithms over distributed datasets.
preventing memory error exploits with wit. attacks often exploit memory errors to gain control over the execution of vulnerable programs. these attacks remain a serious problem despite previous research on techniques to prevent them. we present write integrity testing (wit), a new technique that provides practical protection from these attacks. wit uses points-to analysis at compile time to compute the control-flow graph and the set of objects that can be written by each instruction in the program. then it generates code instrumented to prevent instructions from modifying objects that are not in the set computed by the static analysis, and to ensure that indirect control transfers are allowed by the control-flow graph. to improve coverage where the analysis is not precise enough, wit inserts small guards between the original program objects. we describe an efficient implementation with optimizations to reduce space and time overhead. this implementation can be used in practice because it compiles c and c++ programs without modifications, it has high coverage with no false positives, and it has low overhead. wit's average runtime overhead is only 7% across a set of cpu intensive benchmarks and it is negligible when io is the bottleneck.
pacemakers and implantable cardiac defibrillators: software radio attacks and zero-power defenses. our study analyzes the security and privacy properties of an implantable cardioverter defibrillator (icd). introduced to the u.s. market in 2003, this model of icd includes pacemaker technologyand is designed to communicate wirelessly with a nearby external programmer in the 175 khz frequency range. after partially reverse-engineering the icd's communications protocol with an oscilloscope and a software radio, we implemented several software radio-based attacks that could compromise patient safety and patient privacy. motivated by our desire to improve patient safety, and mindful of conventional trade-offs between security and power consumption for resource-constrained devices, we introduce three new zero-power defenses based on rf power harvesting. two of these defenses are human-centric, bringing patients into the loop with respect to the security and privacy of their implantable medical devices (imds). our contributions provide a scientific baseline for understanding the potential security and privacy risks of current and future imds, and introduce human-perceptible and zero-power mitigation techniques that address those risks. to the best of our knowledge, this paper is the first in our community to use general-purpose software radios to analyze and attack previously unknown radio communications protocols.
automated formal analysis of a protocol for secure file sharing on untrusted storage. we study formal security properties of a state-of-the-art protocol for secure file sharing on untrusted storage, in the automatic protocol verifier proverif. as far as we know, this is the first automated formal analysis of a secure storage protocol. the protocol, designed as the basis for the file system plutus, features a number of interesting schemes like lazy revocation and key rotation. these schemes improve the protocol's performance, but complicate its security properties. our analysis clarifies several ambiguities in the design and reveals some unknown attacks on the protocol. we propose corrections, and prove precise security guarantees for the corrected protocol.
expressive declassification policies and modular static enforcement. this paper provides a way to specify expressive declassification policies, in particular, when, what, and where policies that include conditions under which downgrading is allowed. secondly, an end-to-end semantic property is introduced, based on a model that allows observations of intermediate low states as well as termination. an attacker's knowledge only increases at explicit declassification steps, and within limits set by policy. thirdly, static enforcement is provided by combining type-checking with program verification techniques applied to the small subprograms that carry out declassifications. enforcement is proved sound for a simple programming language and the extension to object-oriented programs is described.
cloaker: hardware supported rootkit concealment. rootkits are used by malicious attackers who desire to run software on a compromised machine without being detected. they have become stealthier over the years as a consequence of the ongoing struggle between attackers and system defenders. in order to explore the next step in rootkit evolution and to build strong defenses, we look at this issue from the point of view of an attacker. we construct cloaker, a proof-of-concept rootkit for the arm platform that is non-persistent and only relies on hardware state modifications for concealment and operation. a primary goal in the design of cloaker is to not alter any part of the host operating system (os) code or data, thereby achieving immunity to all existing rootkit detection techniques which perform integrity, behavior and signature checks of the host os. cloaker also demonstrates that a self-contained execution environment for malicious code can be provided without relying on the host os for any services. integrity checks of hardware state in each of the machine's devices are required in order to detect rootkits such as cloaker. we present a framework for the linux kernel that incorporates integrity checks of hardware state performed by device drivers in order to counter the threat posed by rootkits such as cloaker.
stack and queue integrity on hostile platforms. when computationally intensive tasks have to be carried out on trusted, but limited, platforms such as smart cards, it becomes necessary to compensate for the limited resources (memory, cpu speed) by off-loading implementations of data structures on to an available (but insecure, untrusted) fast coprocessor. however, data structures, such as stacks, queues, rams, and hash tables, can be corrupted (and made to behave incorrectly) by a potentially hostile implementation platform or by an adversary knowing or choosing data structure operations. this paper examines approaches that can detect violations of datastructure invariants, while placing limited demands on the resources of the secure computing platform.
trojan detection using ic fingerprinting. hardware manufacturers are increasingly outsourcing their ic fabrication work overseas due to their much lower cost structure. this poses a significant security risk for ics used for critical military and business applications. attackers can exploit this loss of control to substitute trojan ics for genuine ones or insert a trojan circuit into the design or mask used for fabrication. we show that a technique borrowed from side-channel cryptanalysis can be used to mitigate this problem. our approach uses noise modeling to construct a set of fingerprints for an ic family utilizing sidechannel information such as power, temperature, and electromagnetic (em) profiles. the set of fingerprints can be developed using a few ics from a batch and only these ics would have to be invasively tested to ensure that they were all authentic. the remaining ics are verified using statistical tests against the fingerprints. we describe the theoretical framework and present preliminary experimental results to show that this approach is viable by presenting results obtained by using power simulations performed on representative circuits with several different trojan circuitry. these results show that trojans that are 3-4 orders of magnitude smaller than the main circuit can be detected by signal processing techniques. while scaling our technique to detect even smaller trojans in complex ics with tens or hundreds of millions of transistors would require certain modifications to the ic design process, our results provide a starting point to address this important problem.
gradual release: unifying declassification, encryption and key release policies. information security has a challenge to address: enabling information-flow controls with expressive information release (or declassification) policies. existing approaches tend to address some aspects of information release, exposing the other aspects for possible attacks. it is striking that these approaches fall into two mostly separate categories: revelation-based (as in information purchase, aggregate computation, moves in a game, etc.) and encryption-based declassification (as in sending encrypted secrets over an untrusted network, storing passwords, etc.). this paper introduces gradual release, a policy that unifies declassification, encryption, and key release policies. we model an attacker's knowledge by the sets of possible secret inputs as functions of publicly observable outputs. the essence of gradual release is that this knowledge must remain constant between releases. gradual release turns out to be a powerful foundation for release policies, which we demonstrate by formally connecting revelation-based and encryption-based declassification. furthermore, we show that gradual release can be provably enforced by security types and effects.
information flow in the peer-reviewing process. we investigate a new type of information flow in the electronic publishing process. we show that the use of postscript in this process introduces serious confidentiality issues. in particular, we explain how the reviewer's anonymity in the peer-reviewing process can be compromised by maliciously prepared postscript documents. a demonstration of this attack is available. we briefly discuss how this attack can be extended to other document formats as well.
lurking in the shadows: identifying systemic threats to kernel data. the integrity of kernel code and data is fundamental to the integrity of the computer system. tampering with the kernel data is an attractive venue for rootkit writers since malicious modifications in the kernel are harder to identify compared to their user-level counterparts. so far however, the pattern followed for tampering is limited to hiding malicious objects in user-space. this involves manipulating a subset of kernel data structures that are related to intercepting user requests or affecting the user's view of the system. hence, defense techniques are built around detecting such hiding behavior. the contribution of this paper is to demonstrate a new class of stealthy attacks that only exist in kernel space and do not employ any hiding techniques traditionally used by rootkits. these attacks are stealthy because the damage done to the system is not apparent to the user or intrusion detection systems installed on the system and are symbolic of a more systemic problem present throughout the kernel. our goal in building these attack prototypes was to show that such attacks are not only realistic, but worse; they cannot be detected by the current generation of kernel integrity monitors, without prior knowledge of the attack signature.
ciphertext-policy attribute-based encryption. in several distributed systems a user should only be able to access data if a user posses a certain set of credentials or attributes. currently, the only method for enforcing such policies is to employ a trusted server to store the data and mediate access control. however, if any server storing the data is compromised, then the confidentiality of the data will be compromised. in this paper we present a system for realizing complex access control on encrypted data that we call ciphertext-policy attribute-based encryption. by using our techniques encrypted data can be kept confidential even if the storage server is untrusted; moreover, our methods are secure against collusion attacks. previous attribute- based encryption systems used attributes to describe the encrypted data and built policies into user's keys; while in our system attributes are used to describe a user's credentials, and a party encrypting data determines a policy for who can decrypt. thus, our methods are conceptually closer to traditional access control methods such as role-based access control (rbac). in addition, we provide an implementation of our system and give performance measurements.
extended abstract: provable-security analysis of authenticated encryption in kerberos. kerberos is a widely-deployed network authentication protocol that is being considered for standardization. many works have analyzed its security, identifying flaws and often suggesting fixes, thus helping the protocol's evolution. several recent results present successful formal-methodsbased verification of a significant portion of the current version 5, and some even imply security in the computational setting. for these results to hold, encryption in kerberos should satisfy strong cryptographic security notions. however, neither currently deployed as part of kerberos encryption schemes nor their proposed revisions are known to provably satisfy such notions. we take a close look at kerberos' encryption and confirm that most of the options in the current version provably provide privacy and authenticity, some with slight modification that we suggest. our results complement the formal-methods-based analysis of kerberos that justifies its current design.
endorsed e-cash. an electronic cash (e-cash) scheme lets a user withdraw money from a bank and then spend it anonymously. e-cash can be used only if it can be securely and fairly exchanged for electronic goods or services. in this paper, we introduce and realize endorsed e-cash. an endorsed e-coin consists of a lightweight endorsement x and the rest of the coin which is meaningless without x. we reduce the problem of exchanging e-cash to that of exchanging endorsements. we demonstrate the usefulness of endorsed e-cash by exhibiting simple and efficient solutions to two important problems: (1) optimistic and unlinkable fair exchange of e-cash for digital goods and services; and (2) onion routing with incentives and accountability for the routers. finally, we show how to represent a set of n endorsements using just one endorsement; this means that the complexity of the fair exchange protocol for n coins is the same as for one coin, making e-cash all the more scalable and suitable for applications. our fair exchange of multiple e-coins protocol can be applied to fair exchanges of (almost) any secrets.
fuzzy multi-level security: an experiment on quantified risk-adaptive access control. this paper presents a new model for, or rather a new way of thinking about adaptive, risk-based access control. our basic premise is that there is always inherent uncertainty and risk in access control decisions that is best addressed in an explicit way. we illustrate this concept by showing how the rationale of the well-known, bell-lapadula model based, multi-level security (mls) access control model could be used to develop a risk-adaptive access control model. this new model is more like a fuzzy logic control system [9] than a traditional access control system and hence the name "fuzzy mls". the long version of this paper is published as an ibm research report [3].
shieldgen: automatic data patch generation for unknown vulnerabilities with informed probing. in this paper, we present shieldgen, a system for automatically generating a data patch or a vulnerability signature for an unknown vulnerability, given a zero-day attack instance. the key novelty in our work is that we leverage knowledge of the data format to generate new potential attack instances, which we call probes, and use a zero-day detector as an oracle to determine if an instance can still exploit the vulnerability; the feedback of the oracle guides our search for the vulnerability signature. we have implemented a shieldgen prototype and experimented with three known vulnerabilities. the generated signatures have no false positives and a low rate of false negatives due to imperfect data format specifications and the sampling technique used in our probe generation. overall, they are significantly more precise than the signatures generated by existing schemes. we have also conducted a detailed study of 25 vulnerabilities for which microsoft has issued security bulletins between 2003 and 2006. we estimate that shieldgen can produce high quality signatures for a large portion of those vulnerabilities and that the signatures are superior to the signatures generated by existing schemes.
attacking the ipsec standards in encryption-only configurations. we describe new attacks which break any rfccompliant implementation of ipsec making use of encryption-only esp in tunnel mode. the new attacks are both efficient and realistic: they are ciphertext-only and need only the capability to eavesdrop on esp-encrypted traffic and to inject traffic into the network. we report on our experiences in applying the attacks to a variety of implementations of ipsec.
improving the robustness of private information retrieval. since 1995, much work has been done creating protocols for private information retrieval (pir). many variants of the basic pir model have been proposed, including such modifications as computational vs. information-theoretic privacy protection, correctness in the face of servers that fail to respond or that respond incorrectly, and protection of sensitive data against the database servers themselves. in this paper, we improve on the robustness of pir in a number of ways. first, we present a byzantine-robust pir protocol which provides information-theoretic privacy protection against coalitions of up to all but one of the responding servers, improving the previous result by a factor of 3. in addition, our protocol allows for more of the responding servers to return incorrect information while still enabling the user to compute the correct result. we then extend our protocol so that queries have information-theoretic protection if a limited number of servers collude, as before, but still retain computational protection if they all collude. we also extend the protocol to provide information-theoretic protection to the contents of the database against collusions of limited numbers of the database servers, at no additional communication cost or increase in the number of servers. all of our protocols retrieve a block of data with communication cost only o(.) times the size of the block, where . is the number of servers.