Finding 709 Defects in 258 Projects: An Experience Report on Applying CodeQL to Open-Source Embedded Software (Experience Paper) -- Extended Report

TL;DR

This paper reports on a large-scale empirical study of static analysis tools in open-source embedded software, revealing limited current use, and demonstrating the effectiveness of CodeQL in identifying security defects, with many confirmed and fixed.

Contribution

It provides the first large-scale evaluation of CodeQL in EMBOSS projects, showing its effectiveness and promoting adoption of advanced SAST tools in embedded open-source software.

Findings

CodeQL identified 709 defects across 258 projects.

75% of detected issues were likely security vulnerabilities.

Over half of the defects were confirmed and fixed by developers.

Abstract

In this experience paper, we report on a large-scale empirical study of Static Application Security Testing (SAST) in Open-Source Embedded Software (EMBOSS) repositories. We collected a corpus of 258 of the most popular EMBOSS projects, and then measured their use of SAST tools via program analysis and a survey (N=25) of their developers. Advanced SAST tools are rarely used -- only 3% of projects go beyond trivial compiler analyses. Developers cited the perception of ineffectiveness and false positives as reasons for limited adoption. Motivated by this deficit, we applied the state-of-the-art (SOTA) CodeQL SAST tool and measured its ease of use and actual effectiveness. Across the 258 projects, CodeQL reported 709 true defects with a false positive rate of 34%. There were 535 (75%) likely security vulnerabilities, including in major projects maintained by Microsoft, Amazon, and the Apache Foundation. EMBOSS engineers have confirmed 376 (53%) of these defects, mainly by accepting our pull requests. Two CVEs were issued. Based on these results, we proposed pull requests to include our workflows as part of EMBOSS Continuous Integration (CI) pipelines, 37 (71% of active repositories) of these are already merged. In summary, we urge EMBOSS engineers to adopt the current generation of SAST tools, which offer low false positive rates and are effective at finding security-relevant defects.