Instead of 32-bit IE, this year’s Pwn2Own competition selected 64-bit Internet Explorer as the target for the first time. 64-bit IE brings new challenges to exploit writers, for example, simple heap spraying technique will not work in 64-bit process. And in order to win the game, we also need to bypass the control flow guard (CFG) mitigation on windows 8.1 as well as the enhanced protected mode (EPM) sandbox of IE.