The BlueStacks App Player is designed to enable Android applications to run on Windows PCs and Macintosh computers. Its commonly used to run popular Android games on these platforms. By default the BlueStack installer sets a weak permission to the registry key, which contains InstallDir reg value. This gives a malicious user the ability to modify this value, which can lead to privilege escalation. Since this is a purely local vulnerability which involves no network traffic, Talos has not released any rules for this issue.”]
Source: https://blog.talosintelligence.com/2016/08/bluestacks-app-player-vulnerability.html