Explore the intricacies of UNIX authentication and the Pluggable Authentication Modules (PAM) system in this 22-minute conference talk from RustConf 2022. Delve into the challenges posed by PAM's complex C-based architecture and discover how Rust can be leveraged to extend and improve the authentication stack. Learn about the PAM API, uncover the surprising realities of PAM's inner workings, and gain insights into implementing custom authentication logic using Rust. Examine practical examples of innovative applications for this technology, while also discussing research techniques for uncovering obscure information in the field of system authentication.