Sandworm was a zero-day, because it was apparently seen in a real-world targeted attack before it was fixed by Microsoft. Microsoft patched the vulnerability in Bulletin MS14-060 of Microsofts October 2014 Patch Tuesday. The fix doesn’t work if you have the 64-bit version of PowerPoint on Windows 8 or Windows 8.1, but all other combinations are protected. A Fix it can be added (and removed) simply by clicking a button on the relevant web page.”]
Source: https://nakedsecurity.sophos.com/2014/10/24/has-the-sandworm-exploit-burrowed-back/