@misc{cryptoeprint:2015:905,
author = {Yuval Yarom and Qian Ge and Fangfei Liu and Ruby B. Lee and Gernot Heiser},
title = {Mapping the Intel Last-Level Cache},
howpublished = {Cryptology ePrint Archive, Report 2015/905},
year = {2015},
note = {\url{http://eprint.iacr.org/}},
}
You will need the url.sty package (comes with most LaTeX installations) for the last line. Otherwise, remove the \url command.