  While advanced machine learning (ML) models are deployed in numerous
real-world applications, previous works demonstrate these models have security
and privacy vulnerabilities. Various empirical research has been done in this
field. However, most of the experiments are performed on target ML models
trained by the security researchers themselves. Due to the high computational
resource requirement for training advanced models with complex architectures,
researchers generally choose to train a few target models using relatively
simple architectures on typical experiment datasets. We argue that to
understand ML models' vulnerabilities comprehensively, experiments should be
performed on a large set of models trained with various purposes (not just the
purpose of evaluating ML attacks and defenses). To this end, we propose using
publicly available models with weights from the Internet (public models) for
evaluating attacks and defenses on ML models. We establish a database, namely
SecurityNet, containing 910 annotated image classification models. We then
analyze the effectiveness of several representative attacks/defenses, including
model stealing attacks, membership inference attacks, and backdoor detection on
these public models. Our evaluation empirically shows the performance of these
attacks/defenses can vary significantly on public models compared to
self-trained models. We share SecurityNet with the research community. and
advocate researchers to perform experiments on public models to better
demonstrate their proposed methods' effectiveness in the future.
