Third-party libraries like Log4j accelerate software application development but introduce substantial risk. Vulnerabilities in these libraries have led to Software Supply Chain (SSC) attacks that compromised resources within the host system. These attacks benefit from current application permissions approaches: third-party libraries are implicitly trusted in the application runtime. An application runtime designed with ZeroTrust Architecture (ZTA) principles - secure access to resources, continuous monitoring, and least-privilege enforcement - could mitigate SSC attacks, as it would give zero implicit trust to these libraries. However, no individual security defense incorporates these principles at a low runtime cost. This paper proposes Zero-Trust Dependencies to mitigate SSC vulnerabilities: we apply the NIST ZTA to software applications. First, we assess the expected effectiveness and configuration cost of Zero-Trust Dependencies using a study of third-party software libraries and their vulnerabilities. Then, we present a system design,$\text{ZTD}_{\text{Sys}}$, that enables the application of Zero-Trust Dependencies to software applications and a prototype,$\text{ZTD}_{\text{JAVA}}$, for Java applications. Finally, with evaluations on recreated vulnerabilities and realistic applications, we show that$\text{ZTD}_{\text{JAVA}}$can defend against prevalent vulnerability classes, introduces negligible cost, and is easy to configure and use.

The primary theory of software engineering is that an organization’s Policies and Processes influence the quality of its Products. We call this the PPP Theory. Although empirical software engineering research has grown common, it is unclear whether researchers are trying to evaluate the PPP Theory. To assess this, we analyzed half (33) of the empirical works published over the last two years in three prominent software engineering conferences. In this sample, 70% focus on policies/processes or products, not both. Only 33% provided measurements relating policy/process and products. We make four recommendations: (1) Use PPP Theory in study design; (2) Study feedback relationships; (3) Diversify the studied feed-forward relationships; and (4) Disentangle policy and process. Let us remember that research results are in the context of, and with respect to, the relationship between software products, processes, and policies.