Smt solvers for software security

Computeraided reasoning tools, such as satsmt solvers, have had a dramatic impact on software engineering and security in recent years. Theories solvers for software security, in particular for. Some activelymaintained tools in this category include sage from microsoft research, klee, s2e, and triton. Open tool platform for the cost effective rigorous development of dependable complex software systems services.

Pdf applying smt algorithms to code analysis researchgate. One important application of smt solvers is formal verification, e. Smt solvers as black box oracles to answer questions that encode the essence of problems of static vulnerability checking, exploit generation, and analysis of copy protection. Georgy nosenko an introduction to the use smt solvers for software. Sat and smt solvers can successfully be used to solve a number of practical problems. Some of the bugs remain undetected even after extensive tests with many dynamic debugging tools. Vs3 discovers program invariants with arbitrary, but prespecified, quantification and logical structure. Generating optimal scheduling for wireless sensor networks. Sep 02, 2019 essentially, smt solvers provide a formal approach to exploring and reasoning about complex, interdependent systems.

Fuzzing and deltadebugging smt solvers proceedings of. Such smt solvers are just a leg up on sat solvers by dressing things up in an easierto. These areas are some of the most active in terms of both theoretical research and practical solutions. Security analyses frequently require the ability to reason about string values.

Smt solvers for software security mobius strip reverse. We present vs3, a tool that automatically verifies complex properties of programs and infers maximally weak preconditions and maximally strong postconditions by leveraging the power of smt solvers. I coauthored a paper at woot 12 on applying smt solvers to software security issues. Georgy nosenko an introduction to the use smt solvers for. Smt solvers are useful both for verification, proving the correctness of programs, software testing based on symbolic execution, and for synthesis, generating program fragments by searching over the space of possible programs. The api is optimized for performance using javasmt has very little runtime overhead compared to using the solver api directly, customizability features and settings exposed by various solvers should be visible through the wrapping layer and typesafety it shouldnt be possible to add boolean terms to integer ones at. Usenix is committed to open access to the research presented at our events.

Translation patterns are proposed between sysml structural models, obm, and logical constructs in smtlib, a language used as input to smt solvers. These techniques have bene ted from the rise of powerful specialized reasoning engines such as smt solvers. This talk will give an overview of smt and its applications, and describe a few examples with the aid of the cvc4 solver. Translation patterns are proposed between sysml structural models, obm, and logical constructs in smt lib, a language used as input to smt solvers. Sumit gulwani is a computer scientist seeking connections. Smt solvers are widely used as core engines in many applications. Smt solvers in it security deobfuscating binary code. Smt solvers are useful both for verification, proving the correctness of programs, software. Organise your work, create documents, and discuss everything in one place. Risk management risk management enables you to manage both existing and potential hazards and risks, integrating risk management into organisational processes. Smt solvers have been used successfully in several application areas, such as hardware and software verification, automated test case generation, security, and planning.

Smt solvers handle include linear arithmetic over the in. Smt solvers in it security deobfuscating binary code with logic. Satisfiability modulo theories smt solvers propositional reasoning, via offtheshelf sat solver decision procedures for theories. Such theories are common in vcs and so smt solvers are well suited to automatically proving vcs. Smt solvers for software security woot 2012 take two software updates and see me in the morning. Therefore, robustness and correctness are essential criteria. Most of those solvers are more restrictive than trau in their support for language constraints. Smt solvers extensions to sat solvers with support for variables of nonboolean type offer powerful automation for solving a variety of assurance.

Satsmt solvers and applications university of waterloo. Maplesat, the z3 string solver, mathcheck, and stp. Applications of clp in it security binary obfuscation malware deobfuscation using clp. Symbolic execution as search, and the rise of solvers. Thus this will likely be hard for any smt solver, and demonstrates that software verification is a hard problem in general unless pnp, or at least integer factorization becomes easy. Smt solvers are currently used to prove java vcs in the. In the purely boolean case, a model is a truth assignment to the. Current testing techniques used by developers of smt solvers do not satisfy the high demand for correct and robust solvers, as our testing experiments show. The case for software security evaluations of medical devices usenix healthsec 2011 contributor to practical reverse engineering, chapter 5, obfuscation credited in the preface general reverse engineering publications. Smt solvers for program verification microsoft research. To the best of our knowledge, trau and hampi 1 are the only string solvers which can handle contextfree membership constraints. In the second mode, imhotep smt performs attack detection and secure state estimation at runtime, as.

Some satsmt solvers users at waterloo imeson, tripunitara, garg are using programmatic sat for hardware security krzysztof czarneckis group is using solvers for autocon. Verifying executability of sysml behavior models using. We will consider important software vulnerabilities and attacks that exploit them such as buffer overflows, sql injection, and session hijacking and we will consider defenses that prevent or mitigate these attacks, including advanced testing and program analysis techniques. Javasmt is a common api layer for accessing various smt solvers.

Essentially, smt solvers provide a formal approach to exploring and reasoning about complex, interdependent systems. Finding vulnerabilities, verifying electronic voting machines, program synthesis. Software developed based on these patterns automatically translates sysml models extended with obm into smtlib files. Such software will have welldefined behavior, and that behavior is assured in some way, whether via model checking, testing, or formal verification. Georgy nosenko an introduction to the use smt solvers.

Platform bap for symbolic execution and z3 smt solver as smt solving. Computeraided verification of computer programs often uses smt solvers. Smt solvers for software security openwall community wiki. Applications of smt solvers in software verification, vstte08, toronto, canada 2008 powerpoint slides tutorial on smt solvers in program analysis and verification at microsoft, presented at. Constraint generation and solving been studied in functional programming and compilers 28 but. Contribute to z3proverz3 development by creating an account on github. This course we will explore the foundations of software security. In this article, we present three practical applications of sat to software security in static vulnerability checking, exploit generation, and the study of copy protections. This collaborative project brings together experts in security and in smt to pursue two complementary research goals. However, when it comes to realworld problems, solvers invariably struggle if a naive encoding of the problem is presented to them. It is not a comprehensive survey, but a basic and rigorous introduction to some of the key ideas. Consequently, buffer overflows often lead to many software bugs and serious security holes. Computeraided reasoning tools, such as sat smt solvers, have had a dramatic impact on software engineering and security in recent years.

In this article, we present three practical applications of sat to. Galois is in the business of building trustworthy software. Uf, arithmetic, bitvectors u c uy coinductive datatypes yo undecidable theories. Therefore, it becomes essential to encode certain properties of the domain in order to restrict the search space. Hardware verification at higher levels of abstraction rtl and above verification of analogmixedsignal circuits verification of hybrid systems software model checking software testing security. These tools are now integral to many analysis, synthesis, verification, and testing approaches. Merging smt solvers and programming languages galois, inc. Smt solvers are powerful tools and symbolicconcolic execution can be an effective technique. The user supplies vs3 with a set of predicates and invariant templates. Some smt solvers verit and cvc3 are bundled within the plugin. Such smt solvers are just a leg up on sat solvers by dressing things up in an easiertowrite and easiertoreasonwith language. Filtering false alarms of buffer overflow analysis using smt solvers. So much so that a large number of software engineering tools these days are designed primarily using a sat or smt solver as a backend.

A common technique is to translate preconditions, postconditions, loop conditions, and assertions into smt formulas in order to determine if all properties can hold. Over the last two decades, software engineering broadly construed to include verification, testing, analysis, synthesis, security has witnessed a silent revolution in the form of sat and smt solvers. Using smt solvers to verify highintegrity programs. Care must be taken to avoid socalled matching loops, which may prevent termination of the solver. A highperformance theorem prover from microsoft research. Smt solver which is an automated program analysis technique is increasingly used by vulnerability discovering platforms, especially in the integer security problems checking. Satisfiability modulo theories smt solvers that support quantifier instantiations via matching triggers can be programmed to give practical support for userdefined theories. So i looked up the meaning of the word to make sure i knew what it means and, it turns out, it has nothing to do with a roman triumvirate as i had somehow convinced myself it did.

Experiments in software verification using smt solvers, vs experiments08, toronto, canada 2008 powerpoint slides. Software developed based on these patterns automatically translates sysml models extended with obm into smt lib files. It is not directed at experts but at potential users and developers of smt solvers. Smt solvers for software security george nosenko, security researcher at digital security slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. In this article, we present three practical applications of sat to software security in static vulnerability checking, exploit generation, and the study of copy. Sep 15, 20 unfortunately, i dont know enough about the internals of z3 to know what specifically makes it the fastest smt solver. Breaking algorithms smt solvers for webapp security. Filtering false alarms of buffer overflow analysis using. The primary focus of my research is the theory and practice of mathematical logic reasoning algorithms e. Papers and proceedings are freely available to everyone once the. Computational capacity of modern hardware and algorithmic advances have allowed sat solving to become a tractable technique to rely on for the decision of properties in industrial software. Smt solvers for software security george nosenko, security researcher at digital security 2. Fuzzing and deltadebugging smt solvers proceedings of the.

Those constraints are passed to the smt solver for resolution. Smt solvers for software security proceedings of the 6th usenix. We show that smt solvers are convenient tools to decide many important security queries about programs. Pdf smt solvers for software security researchgate. Over the last several years, i have led the development of four awardwinning solvers that have made significant impact on software engineering, security, and increasingly on combinatorial mathematics. Discuss the applicability of smt satisfiability modulo.

Fuzzing and deltadebugging smt solvers robert brummayer and armin biere. Sat solvers, satisfiability modulo theories smt solvers, and model checkers. Im just curious as to how widespread its become with generalist software developers as a problem solving tool. Nov 19, 20 georgy nosenko an introduction to the use smt solvers for software security 1. Smt analyzes and diagnoses the mathematical description of the dynamical system, by characterizing its security index, that is, the maximum number of attacked sensors that the system can tolerate. But i also dont think its too far wrong to say that smt solvers like z3 are fast because the underlying sat solver they use is very fast. I found it funny that your trifecta has four clauses. Smt solvers for software security proceedings of the 6th. By design, such avoidance limits the extent to which the smt solver is able to apply the. Jul 09, 2017 software verification and testing, nsf workshop on symbolic computation for constraint satisfaction problems, virginia, 2008 powerpoint slides. Smt solvers as black box oracles to an swer questions that encode the essence of problems of static vulnera bility checking, exploit generation, and analysis of copy.

Disruptive innovation in theorem proving, rushby, 2007. Maplesat 2015 present is a sat solver for solving boolean formulas obtained from software engineering and security applications. Vijay ganesh associate professor university of waterloo. In this project, we are investigating the use of formal techniques for assurance of system security, based in particular on computational engines such as boolean satisfiability sat solvers, satisfiability modulo theories smt solvers, and model checkers. Im definitely familiar with z3 and with solvers used offensively and defensively in software security.

Since recent smt solvers such as yices are quite good at solving linear. Generating optimal scheduling for wireless sensor networks by using optimization modulo theories solvers. Smt solvers are useful both for verification, proving the correctness of programs, software testing based on symbolic execution, and for synthesis, generating. Vulnerabilities in widelyused software can leak secret data and violate.

Georgy nosenko an introduction to the use smt solvers for software security 1. Tags reverse engineering, academic, program analysis, smt. A few previous works apply smt formalization to the aforementioned wsn constraints and use smt solvers to generate an. Fuzzing and deltadebugging smt solvers robert brummayer and armin biere institute for formal models and veri cation johannes kepler university linz, austria abstract. Therefore, it is not necessary but still possible to install another copy of these solvers.