Representing LLVM-IR in a Code Property Graph

• Published in: Information Security pp. 360 - 380
• Main Authors: Küchler, Alexander, Banse, Christian
• Format: Book Chapter
• Language: English
• Published: Cham Springer International Publishing
• Series: Lecture Notes in Computer Science
• ISBN: 9783031223891; 3031223896
• ISSN: 0302-9743; 1611-3349
• DOI: 10.1007/978-3-031-22390-7_21

In the past years, a number of static application security testing tools have been proposed which use so-called code property graphs (CPGs), a graph model which keeps rich information about the source code while enabling its user to write language-agnostic analyses. However, they suffer from several shortcomings. They work mostly on source code and exclude the analysis of third-party dependencies if they are only available as compiled binaries. Furthermore, they are limited in their analysis to whether an individual programming language is supported or not. While often support for well-established languages such as C/C++ or Java is included, languages that are still heavily evolving, such as Rust, are not considered because of the constant changes in the language design. To overcome these limitations, we extend an open source implementation of a code property graph to support LLVM-IR which can be used as output by many compilers and binary lifters. In this paper, we discuss how we address challenges that arise when mapping concepts of an intermediate representation to a CPG. At the same time, we optimize the resulting graph to be minimal and close to the representation of equivalent source code. Our case-study on detecting cryptographic misuse indicates that existing analyses can be reused and that the analysis time is comparable to operating on source code. This makes the approach suitable for a security analysis of large-scale projects.