Contents of the PoC are a ".zip" file that is actually plain-text (the engine ignores extension/mime types) and contains just this line of JS and 90kb of nonse

Contents of the PoC are a ".zip" file that is actually plain-text (the engine ignores extension/mime types) and contains just this line of JS and 90kb of nonsense JS for entropy. (new Error()).toString.call({message: 0x41414141 >> 1}) It's hard to imagine MS doesn't receive tons of watson crash reports of MsMpEng from trying to run bits of random JS. If they haven't looked at them, they probably should start now.