Towards Vulnerability Discovery Using Staged Program Analysis

Secure software engineering has emerged in recent decades by encouraging the idea of software security has to be an integral part of all the phases of the software development lifecycle. As a result, each phase of the lifecycle is associated with security-specific best practices such as threat modeling and static code analysis. It was observed that various artifacts (i.e., security requirements, architectural flaws, bug reports, security test cases) generated as a result of security best practices tend to be segregated. This creates a significant barrier to resolve the security issues at the implementation phase since most of them are originated in the design phase. In order to address this issue, this paper presents a knowledge-modeling based approach to semantically infer the associations between architectural level security flaws and code-level security bugs, which is manually tedious. Threat modeling and static analysis are used to identify security flaws and security bugs, respectively. The case study based experimental results revealed that the architectural level security flaws have a significant impact on originating security bugs in the code level. Besides, the evaluation results confirmed the scalability of the proposed approach to large-scale industrial software products.

Static code analysis is widely used to support the development of high-quality software. It helps developers detect potential bugs and security vulnerabilities in a program's source code without executing it. While the potential benefits of static analysis tools are beyond question, their usability is often criticised and prevents software developers from using static analysis to its full potential. In the past decade, researchers have studied developer needs and contrasted them to available static analysis tool functionalities. In this paper, we summarize the main design challenges for building usable static analysis tools, and show that they revolve around the notion of explainability, which is a subarea of usability. We present existing analysis tools and current research in static analysis usability, and detail how they approach those challenges. This leads us to proposing potential lines of future work in explainability for static analysis, namely turning static analysis tools into assistants and teachers.

Static analysis of source code security: Assessment of tools against SAMATE tests

In this article, we present a general method for achieving global static analyzers that are precise and sound, yet also scalable. Our method, on top of the abstract interpretation framework, is a general sparse analysis technique that supports relational as well as nonrelational semantics properties for various programming languages. Analysis designers first use the abstract interpretation framework to have a global and correct static analyzer whose scalability is unattended. Upon this underlying sound static analyzer, analysis designers add our generalized sparse analysis techniques to improve its scalability while preserving the precision of the underlying analysis. Our method prescribes what to prove to guarantee that the resulting sparse version should preserve the precision of the underlying analyzer. We formally present our framework and show that existing sparse analyses are all restricted instances of our framework. In addition, we show more semantically elaborate design examples of sparse nonrelational and relational static analyses. We then present their implementation results that scale to globally analyze up to one million lines of C programs. We also show a set of implementation techniques that turn out to be critical to economically support the sparse analysis process.

A secure software demands effective techniques for vulnerability detection during its development cycle. The practice of detecting security flaws before the deployment phase eliminates the risks that vulnerabilities may impose for the company. Static analysis and dynamic analysis techniques offer two complimentary approaches for checking vulnerabilities. Static analysis involves the scanning of source code or binary eliminating the need of executing it. This approach is fast and has no run time overhead. However, static analysis are quite imprecise and generate huge false positives and false negatives. On the other hand, dynamic analysis involves the running of the software. The problem of false positives and negatives is less in case of dynamic analysis because they analyze by running the test cases. But this approach requires large number of test cases to ensure a certain confidence level in detecting security bugs. This paper describes a methodology which integrates the two approaches in a complimentary manner. It adopts the strengths of the two and eliminates their weaknesses. We are currently dealing with buffer overflow vulnerability with pointer aliasing. However the idea can be extended to other vulnerabilities also for e.g memory related errors, race conditions( Time of Check to Time to Use vulnerability), dangling pointer vulnerability, integer errors etc.

High-coverage testing is challenging. Modern object-oriented programs present additional challenges for testing. One key difficulty is the generation of proper method sequences to construct desired objects as method parameters. In this paper, we cast the problem as an instance of program synthesis that automatically generates candidate programs to satisfy a user-specified intent. In our setting, candidate programs are method sequences, and desired object states specify an intent. Automatic generation of desired method sequences is difficult due to its large search space---sequences often involve methods from multiple classes and require specific primitive values. This paper introduces a novel approach, called Seeker, to intelligently navigate the large search space. Seeker synergistically combines static and dynamic analyses: (1) dynamic analysis generates method sequences to cover branches; (2) static analysis uses dynamic analysis information for not-covered branches to generate candidate sequences; and (3) dynamic analysis explores and eliminates statically generated sequences. For evaluation, we have implemented Seeker and demonstrate its effectiveness on four subject applications totalling 28K LOC. We show that Seeker achieves higher branch coverage and def-use coverage than existing state-of-the-art approaches. We also show that Seeker detects 34 new defects missed by existing tools.

Code flaws or vulnerabilities are prevalent in software systems and can potentially cause a variety of problems including deadlock, hacking, information loss and system failure. A variety of approaches have been developed to try and detect the most likely locations of such code vulnerabilities in large code bases. Most of them rely on manually designing code features (e.g., complexity metrics or frequencies of code tokens) that represent the characteristics of the potentially problematic code to locate. However, all suffer from challenges in sufficiently capturing both semantic and syntactic representation of source code, an important capability for building accurate prediction models. In this paper, we describe a new approach, built upon the powerful deep learning Long Short Term Memory model, to automatically learn both semantic and syntactic features of code. Our evaluation on 18 Android applications and the Firefox application demonstrates that the prediction power obtained from our learned features is better than what is achieved by state of the art vulnerability prediction models, for both within-project prediction and cross-project prediction.

In this article we present a general method for achieving global static analyzers that are precise, sound, yet also scalable. Our method generalizes the sparse analysis techniques on top of the abstract interpretation framework to support relational as well as non-relational semantics properties for C-like languages. We first use the abstract interpretation framework to have a global static analyzer whose scalability is unattended. Upon this underlying sound static analyzer, we add our generalized sparse analysis techniques to improve its scalability while preserving the precision of the underlying analysis. Our framework determines what to prove to guarantee that the resulting sparse version should preserve the precision of the underlying analyzer. We formally present our framework; we present that existing sparse analyses are all restricted instances of our framework; we show more semantically elaborate design examples of sparse non-relational and relational static analyses; we present their implemen- tation results that scale to analyze up to one million lines of C programs. We also show a set of implementation techniques that turn out to be critical to economically support the sparse analysis process.

A scalable learning algorithm for data-driven program analysis

Discovering and eliminating critical vulnerabilities in program code is a key requirement for the secure operation of software systems. This task rests primarily on the shoulders of experienced code analysts who inspect programs in-depth to identify weaknesses. As software systems grow in complexity, while the amount of security critical code increases, supplying these analysts with effective methods to assist in their work becomes even more crucial. Unfortunately, exact methods for automated software analysis are rarely of help in practice, as they do not scale to the complexity of contemporary software projects, and are not designed to benefit from the analyst's domain knowledge. To address this problem, we present pattern-based vulnerability discovery, a novel approach of devising assistant methods for vulnerability discovery that are build with a high focus on practical requirements. The approach combines techniques of static analysis, machine learning, and graph mining to lend imprecise but highly effective methods that allow analysts to benefit from the machine's pattern recognition abilities without sacrificing the strengths of manual analysis.

Industrial robots are complex and customizable machines that can be programmed with proprietary domain-specific languages. These languages provide not only movement instructions, but also access to low-level system resources such as the network or the file system. Although useful, these features can lead to taint-style vulnerabilities and can be misused to implement malware---on par with general-purpose programming languages. In this paper, we analyze the languages of $8$ leading industrial robot vendors, systematize their technical features, and discuss cases of vulnerable and malicious uses. We then describe a static source-code analyzer that we created to analyze robotic programs and discover insecure or potentially malicious code paths. We focused our proof-of-concept implementation on two popular languages, namely ABB's RAPID and KUKA's KRL. By evaluating our tool on a set of publicly available programs, we show that insecure patterns are found in real-world code; therefore, static source-code analysis is an effective security screening mechanism, for example to prevent commissioning insecure or malicious industrial task programs. Finally, we discuss remediation steps that developers and vendors can adopt to mitigate such issues.

The specification language is a critical component of the hardware-software co-design process since it is used for functional validation and as a starting point for hardware-software partitioning and co-synthesis. The paper proposes the Java programming language as a specification language for hardware-software systems. Java has several characteristics that make it suitable for system specification. However static control and data flow analysis of Java programs is problematic because Java classes are dynamically linked. The paper provides a general solution to the problem of statically analyzing Java programs using a technique that pre-allocates most class instances and aggressively resolves memory aliasing using global analysis. The output of the analysis is a control data flow graph for the input specification. The results for sample designs show that the analysis can extract fine to coarse-grained concurrency for subsequent hardware-software partitioning and co-synthesis steps of the hardware-software co-design process to exploit.

We present a framework for the application of abstract interpretation as an aid during program development, rather than in the more traditional application of program optimization. Program validation and detection of errors is first performed statically by comparing (partial) specifications written in terms of assertions against information obtained from static analysis of the program. The results of this process are expressed in the user assertion language. Assertions (or parts of assertions) which cannot be verified statically are translated into run-time tests. The framework allows the use of assertions to be optional. It also allows using very general properties in assertions, beyond the predefined set understandable by the static analyzer and including properties defined by means of user programs. We also report briefly on an implementation of the framework. The resulting tool generates and checks assertions for Prolog, CLP(R), and CHIP/CLP(fd) programs, and integrates compile-time and run-time checking in a uniform way. The tool allows using properties such as types, modes, non-failure, determinacy, and computational cost, and can treat modules separately, performing incremental analysis. In practice, this modularity allows detecting statically bugs in user programs even if they do not contain any assertions.

Programming languages such as Java and C# execute code with different levels of trust in the same process, and rely on an access control model with fine-grained permissions to protect program code. Permissions are checked programmatically, and rely on programmer discipline. This can lead to subtle errors. To enable automatic security analysis about unauthorised access or information flow, it is necessary to reason about security-sensitive entities in libraries that must be protected by appropriate sanitisation/declassification via permission checks. Unfortunately, security-sensitive entities are not clearly identified. In this paper, we investigate security-sensitive entities used in Java-like languages, and develop a static program analysis technique to identify them in large codebases by analysing the patterns of permission checks. Although the technique is generic, our focus is on Java where checkPermission calls are used to guard potential security-sensitive entities. Our inference analysis uses two parameters called proximity and coverage to reduce false-positive and false-negative reports. The usefulness of the analysis is illustrated by the results obtained while checking the OpenJDK7-b147 for conformance to Java Secure Coding Guidelines that relate to the confidentiality and integrity requirements.

In this paper, we describe a computer science curricular framework for creating innovative, four-year computer science programs for high school computer science courses. Based on a suggested set of great principles of computing by Peter Denning, the framework is structured as a stack of four curricular layers. The result is a framework design that provides a high degree of curricular and pedagogical flexibility, particularly suited for the rapidly changing discipline of computer science. This report describes the computer science curricular framework, the implementation of the framework and the deployment of a four-year curriculum from the implemented framework. Initial classroom experiences are reported.