Welcome to the documentation of the code analysis platform Joern! For a high-level overview, please also check out https://joern.io .

Joern is a platform for robust analysis of C/C++ code. It generates code property graphs, a graph representation of code for cross-language code analysis. Code property graphs are stored in a custom graph database. This allows code to be mined using search queries formulated in a Scala-based domain-specific query language. Joern is developed with the goal of providing a useful tool for vulnerability discovery and research in static program analysis.

The core features of Joern are:

  • Fuzzy Parsing of C/C++. Joern employs a fuzzy parser for C/C++ based on the concept of Island grammars. The parser enables importing arbitrary code even if a working build environment cannot be supplied or parts of the code are missing.

  • Code Property Graphs. Joern creates semantic code property graphs from the fuzzy parser output and stores them in an in-memory graph database. SCPGs are a language-agnostic intermediate representation of code designed for query-based code analysis.

  • Search Queries. Joern offers a stronly-typed Scala-based extensible query language for code analysis based on Gremlin-Scala. This language can be used to manually formulate search queries for vulnerabilities as well as automatically infer them using machine learning techniques.

  • Extendable via CPG passes. Code property graphs are multi-layered, offering information about code on different levels of abstraction. Joern comes with many default passes, but also allows users to add passes to include additional information in the graph, and extend the query language accordingly.