An anonymous reader writes: Microsoft researchers have published a paper (pdf link here) entitled "De-anonymizing the Internet Using Unreliable IDs," where they say they can track hackers or malicious content to the original host with 99% accuracy. From the abstract, "In this paper, we present a system called HostTracker that tracks dynamic bindings between hosts and IP addresses by leveraging application-level data with unreliable IDs. Using a month-long user login trace from a large email provider, we show that HostTracker can attribute most of the activities reliably to the responsible hosts, despite the existence of dynamic IP addresses, proxies, and NATs. With this information, we are able to analyze the host population, to conduct forensic analysis, and also to blacklist malicious hosts dynamically." One wonders what else this can be used for.