Deploying fuzzing within CI/CD pipelines can help ensure safe and secure code evolution. Directed greybox fuzzing techniques such as AFLGo are a good match for the CI/CD context. These techniques prioritise inputs based on estimated distances to the changed code. Unfortunately, computing these distances is often expensive, making the techniques impractical for short CI/CD runs.

In this paper, we propose an AFLGo-based technique called PaZZER, which optimises the distance calculation by dropping the expensive control-flow graph component and computing the call-graph component in an incremental fashion. Preliminary results are promising, showing that PaZZER can make CI/CD testing feasible for large applications: eg. for objdump the distance computation time is decreased from 34 min to just 2.5 min, with a further 2.3 min saved when an incremental algorithm is used. The significant time reduction in distance computation allows PaZZER to use most of the time on actual fuzzing, making it practical for short CI/CD runs of around 10 minutes.

Our planned full evaluation will involve real-world commits from a diverse set of 9 applications of different sizes. This will include coverage experiments and an ablation study to investigate the impact of PaZZER’s design decisions, and a bug-finding case study comparing it against AFLGo and Google’s CIFuzz. We will assess the benefits and effectiveness of our approach in terms of patch coverage, patch proximity, distance computation time, and time-to-exposure for bugs.