The link knows all.

Muhammad Danish, University of New Mexico lead author and cybersecurity researcher, discussing his team's work on "Private Links, Public Leaks: Consequences of Frictionless User Experience on the Security and Privacy Posture of SMS-Delivered URLs". This paper examines how the push for frictionless user experiences has led many services to rely on SMS-delivered, single-click URLs—an inherently insecure channel that can be intercepted or leaked. Analyzing more than 322,000 unique URLs from 33 million messages, the researchers found widespread security failures, including exposed PII across 701 endpoints at 177 services due to weak, token-based authentication that treats possession of a link as sufficient authorization. The study also identified low-entropy tokens enabling mass URL enumeration and data overfetching issues, though disclosures prompted 18 services to fix flaws, improving privacy protections for at least 120 million users. The research can be found here: ⁠Private Links, Public Leaks: Consequences of Frictionless User Experience on the Security and Privacy Posture of SMS-Delivered URLs