The guest-app-ui npm package version 99.0.0 contains malicious code that executes during installation. It collects host identifiers such as hostname, user environment variables, current working directory, platform details, and internal IP addresses. This data is encoded and sent to a hardcoded external server via DNS queries and HTTP/HTTPS POST requests, with TLS verification disabled for HTTPS. The package uses a name that can cause dependency confusion, potentially leading organizations with private packages of the same name to inadvertently install this malicious public package. The malicious behavior is unconditional and not gated by any authorization checks.