Now, researchers have devised an attack that could spell the end of ASLR as the world knows it now. The attack uses simple JavaScript code to identify the memory addresses where system and application components are loaded. When combined with attack code that exploits vulnerabilities in browsers or operating systems, the JavaScript can reliably eliminate virtually all of the protection ASLR provides. New JavaScript Code Could Make Drive-By Exploits Much Worse [arstechnica.com]