Nit: asm.js (http://asmjs.org/ http://asmjs.org/) is low-level JavaScript - a subset of JavaScript which is explicitly compiled into equivalent machine code ahe

Nit: asm.js (http://asmjs.org/ http://asmjs.org/) is low-level JavaScript - a subset of JavaScript which is explicitly compiled into equivalent machine code ahead-of-time by supporting browsers (and interpreted otherwise). asm.js imposes significant restrictions on JavaScript in order to produce efficiently compilable code, and its operations map almost 1:1 to machine instructions. And as you correctly note, the ransomware code does not come close to qualifying as "low-level".