I was reading my textbook, Katz and Lindell's Intro to Modern Cryptography in the section about Message Authentication Codes. They were talking about timing attacks in general and brought up an example (page 116):
One might wonder whether this attack is realistic, as it requires access to a verification oracle as well as the ability to measure the difference in time taken to compare i vs. i + 1 bytes. In fact, exactly such attacks have been carried out against real systems! As just one example, MACs were used to verify code updates in the Xbox 360, and the implementation of MAC verification used there had a difference of 2.2 milliseconds between rejection times. Attackers were able to exploit this and load pirated games onto the hardware.
That struck me as really interesting, and I wanted to learn more, but I couldn't find any citation in the references, nor did I find anything online. Is there any more detail about how this attack worked?