We present Nail, an interface generator that allows programmers to safely parse and generate protocols defined by a Parser-Expression based grammar. Nail uses a richer set of parser combinators that induce an internal representation, obviating the need to write semantic actions. Nail also provides solutions parsing common patterns such as length and offset fields within binary formats that are hard to process with existing parser generators.
{"title":"Nail: A Practical Interface Generator for Data Formats","authors":"Julian Bangert, N. Zeldovich","doi":"10.1109/SPW.2014.31","DOIUrl":"https://doi.org/10.1109/SPW.2014.31","url":null,"abstract":"We present Nail, an interface generator that allows programmers to safely parse and generate protocols defined by a Parser-Expression based grammar. Nail uses a richer set of parser combinators that induce an internal representation, obviating the need to write semantic actions. Nail also provides solutions parsing common patterns such as length and offset fields within binary formats that are hard to process with existing parser generators.","PeriodicalId":142224,"journal":{"name":"2014 IEEE Security and Privacy Workshops","volume":"62 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131903744","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A parser's job is to take unstructured, opaque data and convert it to a structured, semantically meaningful format. As such, parsers often operate at the border between untrusted data sources (e.g., the Internet) and the soft, chewy center of computer systems, where performance and security are paramount. A firewall, for instance, is precisely a trust-creating parser for Internet protocols, permitting valid packets to pass through and dropping or actively rejecting malformed packets. Despite the prevalence of finite state machines (FSMs) in both protocol specifications and protocol implementations, they have gained little traction in parser code for such protocols. Typical reasons for avoiding the FSM computation model claim poor performance, poor scalability, poor expressibility, and difficult or time-consuming programming. In this research report, we present our motivations for and designs of finite state machines to parse a variety of existing Internet protocols, both binary and ASCII. Our hand-written parsers explicitly optimize around L1 cache hit latency, branch misprediction penalty, and program-wide memory overhead to achieve aggressive performance and scalability targets. Our work demonstrates that such parsers are, contrary to popular belief, sufficiently expressive for meaningful protocols, sufficiently performant for high-throughput applications, and sufficiently simple to construct and maintain. We hope that, in light of other research demonstrating the security benefits of such parsers over more complex, Turing-complete codes, our work serves as evidence that certain ``practical'' reasons for avoiding FSM-based parsers are invalid.
{"title":"Finite State Machine Parsing for Internet Protocols: Faster Than You Think","authors":"R. Graham, Peter C. Johnson","doi":"10.1109/SPW.2014.34","DOIUrl":"https://doi.org/10.1109/SPW.2014.34","url":null,"abstract":"A parser's job is to take unstructured, opaque data and convert it to a structured, semantically meaningful format. As such, parsers often operate at the border between untrusted data sources (e.g., the Internet) and the soft, chewy center of computer systems, where performance and security are paramount. A firewall, for instance, is precisely a trust-creating parser for Internet protocols, permitting valid packets to pass through and dropping or actively rejecting malformed packets. Despite the prevalence of finite state machines (FSMs) in both protocol specifications and protocol implementations, they have gained little traction in parser code for such protocols. Typical reasons for avoiding the FSM computation model claim poor performance, poor scalability, poor expressibility, and difficult or time-consuming programming. In this research report, we present our motivations for and designs of finite state machines to parse a variety of existing Internet protocols, both binary and ASCII. Our hand-written parsers explicitly optimize around L1 cache hit latency, branch misprediction penalty, and program-wide memory overhead to achieve aggressive performance and scalability targets. Our work demonstrates that such parsers are, contrary to popular belief, sufficiently expressive for meaningful protocols, sufficiently performant for high-throughput applications, and sufficiently simple to construct and maintain. We hope that, in light of other research demonstrating the security benefits of such parsers over more complex, Turing-complete codes, our work serves as evidence that certain ``practical'' reasons for avoiding FSM-based parsers are invalid.","PeriodicalId":142224,"journal":{"name":"2014 IEEE Security and Privacy Workshops","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133992499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Parsers for complex data formats generally present a big attack surface for input-driven exploitation. In practice, this has been especially true for implementations of the PDF data format, as witnessed by dozens of known vulnerabilities exploited in many real world attacks, with the Acrobat Reader implementation being the main target. In this report, we describe our attempts to use Coq, a theorem prover based on a functional programming language making use of dependent types and the Curry-Howard isomorphism, to implement a formally verified PDF parser. We ended up implementing a subset of the PDF format and proving termination of the combinator-based parser. Noteworthy results include a dependent type representing a list of strictly monotonically decreasing length of remaining symbols to parse, which allowed us to show termination of parser combinators. Also, difficulties showing termination of parsing some features of the PDF format readily translated into denial of service attacks against existing PDF parsers-we came up with a single PDF file that made all the existing PDF implementations we could test enter an endless loop.
{"title":"The Pitfalls of Protocol Design: Attempting to Write a Formally Verified PDF Parser","authors":"Andreas Bogk, Marco Schopl","doi":"10.1109/SPW.2014.36","DOIUrl":"https://doi.org/10.1109/SPW.2014.36","url":null,"abstract":"Parsers for complex data formats generally present a big attack surface for input-driven exploitation. In practice, this has been especially true for implementations of the PDF data format, as witnessed by dozens of known vulnerabilities exploited in many real world attacks, with the Acrobat Reader implementation being the main target. In this report, we describe our attempts to use Coq, a theorem prover based on a functional programming language making use of dependent types and the Curry-Howard isomorphism, to implement a formally verified PDF parser. We ended up implementing a subset of the PDF format and proving termination of the combinator-based parser. Noteworthy results include a dependent type representing a list of strictly monotonically decreasing length of remaining symbols to parse, which allowed us to show termination of parser combinators. Also, difficulties showing termination of parsing some features of the PDF format readily translated into denial of service attacks against existing PDF parsers-we came up with a single PDF file that made all the existing PDF implementations we could test enter an endless loop.","PeriodicalId":142224,"journal":{"name":"2014 IEEE Security and Privacy Workshops","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130764484","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
F. Greitzer, Jeremy R. Strozer, Sholom G. Cohen, A. Moore, David A. Mundie, Jennifer Cowley
Organizations often suffer harm from individuals who bear no malice against them but whose actions unintentionally expose the organizations to risk-the unintentional insider threat (UIT). In this paper we examine UIT cases that derive from social engineering exploits. We report on our efforts to collect and analyze data from UIT social engineering incidents to identify possible behavioral and technical patterns and to inform future research and development of UIT mitigation strategies.
{"title":"Analysis of Unintentional Insider Threats Deriving from Social Engineering Exploits","authors":"F. Greitzer, Jeremy R. Strozer, Sholom G. Cohen, A. Moore, David A. Mundie, Jennifer Cowley","doi":"10.1109/SPW.2014.39","DOIUrl":"https://doi.org/10.1109/SPW.2014.39","url":null,"abstract":"Organizations often suffer harm from individuals who bear no malice against them but whose actions unintentionally expose the organizations to risk-the unintentional insider threat (UIT). In this paper we examine UIT cases that derive from social engineering exploits. We report on our efforts to collect and analyze data from UIT social engineering incidents to identify possible behavioral and technical patterns and to inform future research and development of UIT mitigation strategies.","PeriodicalId":142224,"journal":{"name":"2014 IEEE Security and Privacy Workshops","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114206363","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Parsers are pervasive software basic blocks: as soon as a program needs to communicate with another program or to read a file, a parser is involved. However, writing robust parsers can be difficult, as is revealed by the amount of bugs and vulnerabilities related to programming errors in parsers. It is especially true for network analysis tools, which led the network and protocols laboratory of the French Network and Information Security Agency (ANSSI) to write custom tools. One of them, Parsifal, is a generic framework to describe parsers in OCaml, and gave us some insight into binary formats and parsers. After describing our tool, this article presents some use cases and lessons we learned about format complexity, parser robustness and the role the language used played.
{"title":"Parsifal: A Pragmatic Solution to the Binary Parsing Problems","authors":"O. Levillain","doi":"10.1109/SPW.2014.35","DOIUrl":"https://doi.org/10.1109/SPW.2014.35","url":null,"abstract":"Parsers are pervasive software basic blocks: as soon as a program needs to communicate with another program or to read a file, a parser is involved. However, writing robust parsers can be difficult, as is revealed by the amount of bugs and vulnerabilities related to programming errors in parsers. It is especially true for network analysis tools, which led the network and protocols laboratory of the French Network and Information Security Agency (ANSSI) to write custom tools. One of them, Parsifal, is a generic framework to describe parsers in OCaml, and gave us some insight into binary formats and parsers. After describing our tool, this article presents some use cases and lessons we learned about format complexity, parser robustness and the role the language used played.","PeriodicalId":142224,"journal":{"name":"2014 IEEE Security and Privacy Workshops","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126014008","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Within the last decade, there are growing economic social incentives and opportunities for secondary use of data in many sectors, and strong market forces currently drive the active development of systems that aggregate user data gathered by many sources. This secondary use of data poses privacy threats due to unwanted use of data for the wrong purposes such as discriminating the user for employment, loan and insurance. Traditional privacy policy languages such as the Platform for Privacy Preferences (P3P) are inadequate since they were designed long before many of these technologies were invented and basically focus on enabling user-awareness and control during primary data collection (e.g. by a website). However, with the advent of Web 2.0 and Social Networking Sites, the landscape of privacy is shifting from limiting collection of data by websites to ensuring ethical use of the data after initial collection. To meet the current challenges of privacy protection in secondary context, we propose a privacy policy language, Purpose-to-Use (P2U), aimed at enforcing privacy while enabling secondary user information sharing across applications, devices, and services on the Web.
{"title":"P2U: A Privacy Policy Specification Language for Secondary Data Sharing and Usage","authors":"J. Iyilade, Julita Vassileva","doi":"10.1109/SPW.2014.12","DOIUrl":"https://doi.org/10.1109/SPW.2014.12","url":null,"abstract":"Within the last decade, there are growing economic social incentives and opportunities for secondary use of data in many sectors, and strong market forces currently drive the active development of systems that aggregate user data gathered by many sources. This secondary use of data poses privacy threats due to unwanted use of data for the wrong purposes such as discriminating the user for employment, loan and insurance. Traditional privacy policy languages such as the Platform for Privacy Preferences (P3P) are inadequate since they were designed long before many of these technologies were invented and basically focus on enabling user-awareness and control during primary data collection (e.g. by a website). However, with the advent of Web 2.0 and Social Networking Sites, the landscape of privacy is shifting from limiting collection of data by websites to ensuring ethical use of the data after initial collection. To meet the current challenges of privacy protection in secondary context, we propose a privacy policy language, Purpose-to-Use (P2U), aimed at enforcing privacy while enabling secondary user information sharing across applications, devices, and services on the Web.","PeriodicalId":142224,"journal":{"name":"2014 IEEE Security and Privacy Workshops","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124025909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Security and privacy are not only general requirements of a society but also indispensable enablers for innovative IT infrastructure applications aiming at increased, sustainable welfare and safety of a society. A critical activity of these IT applications is spontaneous information exchange. This information exchange, however, creates inevitable, unknown dependencies between the participating IT systems, which, in turn threaten security and privacy. With the current approach to IT security, security and privacy follow changes and incidents rather than anticipating them. By sticking to a given threat model, the current approach fails to consider vulnerabilities which arise during a spontaneous information exchange. With the goal of improving security and privacy, this work proposes adapting an IT security model and its enforcement to current and most probable incidents before they result in an unacceptable risk for the participating parties or failure of IT applications. Usage control is the suitable security policy model, since it allows changes during run-time without conceptually raising additional incidents.
{"title":"Resilience as a New Enforcement Model for IT Security Based on Usage Control","authors":"Sven Wohlgemuth","doi":"10.1109/SPW.2014.14","DOIUrl":"https://doi.org/10.1109/SPW.2014.14","url":null,"abstract":"Security and privacy are not only general requirements of a society but also indispensable enablers for innovative IT infrastructure applications aiming at increased, sustainable welfare and safety of a society. A critical activity of these IT applications is spontaneous information exchange. This information exchange, however, creates inevitable, unknown dependencies between the participating IT systems, which, in turn threaten security and privacy. With the current approach to IT security, security and privacy follow changes and incidents rather than anticipating them. By sticking to a given threat model, the current approach fails to consider vulnerabilities which arise during a spontaneous information exchange. With the goal of improving security and privacy, this work proposes adapting an IT security model and its enforcement to current and most probable incidents before they result in an unacceptable risk for the participating parties or failure of IT applications. Usage control is the suitable security policy model, since it allows changes during run-time without conceptually raising additional incidents.","PeriodicalId":142224,"journal":{"name":"2014 IEEE Security and Privacy Workshops","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115295716","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We review different attack vectors on Proof-Carrying Code (PCC) related to policy, memory model, machine abstraction, and formal system. We capture the notion of weird machines in PCC to formalize the shadow execution arising in programs when their proofs do not sufficiently capture and disallow the execution of untrusted computations. We suggest a few ideas to improve existing PCC systems so they are more resilient to memory attacks.
{"title":"The Weird Machines in Proof-Carrying Code","authors":"Julien Vanegue","doi":"10.1109/SPW.2014.37","DOIUrl":"https://doi.org/10.1109/SPW.2014.37","url":null,"abstract":"We review different attack vectors on Proof-Carrying Code (PCC) related to policy, memory model, machine abstraction, and formal system. We capture the notion of weird machines in PCC to formalize the shadow execution arising in programs when their proofs do not sufficiently capture and disallow the execution of untrusted computations. We suggest a few ideas to improve existing PCC systems so they are more resilient to memory attacks.","PeriodicalId":142224,"journal":{"name":"2014 IEEE Security and Privacy Workshops","volume":"2010 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127343727","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jason R. C. Nurse, Oliver Buckley, P. Legg, M. Goldsmith, S. Creese, Gordon R. T. Wright, M. Whitty
The threat that insiders pose to businesses, institutions and governmental organisations continues to be of serious concern. Recent industry surveys and academic literature provide unequivocal evidence to support the significance of this threat and its prevalence. Despite this, however, there is still no unifying framework to fully characterise insider attacks and to facilitate an understanding of the problem, its many components and how they all fit together. In this paper, we focus on this challenge and put forward a grounded framework for understanding and reflecting on the threat that insiders pose. Specifically, we propose a novel conceptualisation that is heavily grounded in insider-threat case studies, existing literature and relevant psychological theory. The framework identifies several key elements within the problem space, concentrating not only on noteworthy events and indicators- technical and behavioural- of potential attacks, but also on attackers (e.g., the motivation behind malicious threats and the human factors related to unintentional ones), and on the range of attacks being witnessed. The real value of our framework is in its emphasis on bringing together and defining clearly the various aspects of insider threat, all based on real-world cases and pertinent literature. This can therefore act as a platform for general understanding of the threat, and also for reflection, modelling past attacks and looking for useful patterns.
{"title":"Understanding Insider Threat: A Framework for Characterising Attacks","authors":"Jason R. C. Nurse, Oliver Buckley, P. Legg, M. Goldsmith, S. Creese, Gordon R. T. Wright, M. Whitty","doi":"10.1109/SPW.2014.38","DOIUrl":"https://doi.org/10.1109/SPW.2014.38","url":null,"abstract":"The threat that insiders pose to businesses, institutions and governmental organisations continues to be of serious concern. Recent industry surveys and academic literature provide unequivocal evidence to support the significance of this threat and its prevalence. Despite this, however, there is still no unifying framework to fully characterise insider attacks and to facilitate an understanding of the problem, its many components and how they all fit together. In this paper, we focus on this challenge and put forward a grounded framework for understanding and reflecting on the threat that insiders pose. Specifically, we propose a novel conceptualisation that is heavily grounded in insider-threat case studies, existing literature and relevant psychological theory. The framework identifies several key elements within the problem space, concentrating not only on noteworthy events and indicators- technical and behavioural- of potential attacks, but also on attackers (e.g., the motivation behind malicious threats and the human factors related to unintentional ones), and on the range of attacks being witnessed. The real value of our framework is in its emphasis on bringing together and defining clearly the various aspects of insider threat, all based on real-world cases and pertinent literature. This can therefore act as a platform for general understanding of the threat, and also for reflection, modelling past attacks and looking for useful patterns.","PeriodicalId":142224,"journal":{"name":"2014 IEEE Security and Privacy Workshops","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115492153","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Dietrich, J. V. D. Ham, A. Pras, R. V. Rijswijk-Deij, Darren Shou, A. Sperotto, A. Wynsberghe, L. Zuck
As an outcome of a seminar on the 'Ethics in Data Sharing', we sketch a model of best practice for sharing data in research. We illustrate this model with two current and timely real-life cases from the context of computer and network security.
{"title":"Ethics in Data Sharing: Developing a Model for Best Practice","authors":"S. Dietrich, J. V. D. Ham, A. Pras, R. V. Rijswijk-Deij, Darren Shou, A. Sperotto, A. Wynsberghe, L. Zuck","doi":"10.1109/SPW.2014.43","DOIUrl":"https://doi.org/10.1109/SPW.2014.43","url":null,"abstract":"As an outcome of a seminar on the 'Ethics in Data Sharing', we sketch a model of best practice for sharing data in research. We illustrate this model with two current and timely real-life cases from the context of computer and network security.","PeriodicalId":142224,"journal":{"name":"2014 IEEE Security and Privacy Workshops","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130301430","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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