OSS-Fuzz

OSS-Fuzz is an open-source project developed by Google that provides free distributed infrastructure for continuous fuzz testing. It streamlines the fuzzing process and facilitates simpler modifications. While only select projects are accepted into OSS-Fuzz, the project's core is open-source, allowing anyone to host their own instance for private projects.

Overview

OSS-Fuzz provides a simple CLI framework for building and starting harnesses or calculating their coverage. Additionally, OSS-Fuzz can be used as a service that hosts static web pages generated from fuzzing outputs such as coverage information.

Key Concepts

Concept	Description
helper.py	CLI script for building images, building fuzzers, and running harnesses locally
Base Images	Hierarchical Docker images providing build dependencies and compilers
project.yaml	Configuration file defining project metadata for OSS-Fuzz enrollment
Dockerfile	Project-specific image with build dependencies
build.sh	Script that builds fuzzing harnesses for your project
Criticality Score	Metric used by OSS-Fuzz team to evaluate project acceptance

When to Apply

Apply this technique when:

• Setting up continuous fuzzing for an open-source project
• Need distributed fuzzing infrastructure without managing servers
• Want coverage reports and bug tracking integrated with fuzzing
• Testing existing OSS-Fuzz harnesses locally
• Reproducing crashes from OSS-Fuzz bug reports

Skip this technique when:

• Project is closed-source (unless hosting your own OSS-Fuzz instance)
• Project doesn't meet OSS-Fuzz's criticality score threshold
• Need proprietary or specialized fuzzing infrastructure
• Fuzzing simple scripts that don't warrant infrastructure

Quick Reference