Attack allows an attacker to create a mouse-over in a PowerPoint file that triggers the installation of malware. Microsoft does not consider this a vulnerability. Independent security researcher Mandar Satam, who created a proof-of-concept attack using the technique, said the weakness is in PowerPoint s Open XML Slide Show files, called PPSX. These type of PowerPoint files are designed for presentation playback only, and can t be edited. Satam bypasses previous PowerPoint restrictions implemented by Microsoft in 2017, to prevent malicious links in PowerPoint from installing local programs.
Source: https://threatpost.com/powerpoint-weakness-mouse-over-attack/154589/