New Snowden doc details how British intelligence tracked iPhone users


Before Apple decided that it wanted to do away with the UDID system, it was one of the best tools British intelligence agents had to track iPhone users across various services, according to a new document (PDF) leaked by Edward Snowden and published in Der Spiegel. The report, dated November 2010, details how "the iPhone Unique Device Identifier (UDID) can be used for target tracking and can be used to correlate with end point machines and target phone," the report's summer notes.

Britian's GCHQ (Government Communications Headquarters) discovered that by watching for a specific device's UDID to pop up via a compromised computer or web browser and further nail down an individual's patterns and common locations. The UDID system essentially left a trail of digital breadcrumbs that could easily be tracked with the GCHQ's systems.

The full report is of course very technical but definitely worth a read anyway, as it offers an interesting glimpse of the behind-the-curtain work to crack mobile tracking.