Employees endanger spreadsheet data when they connect away from the office to the less secure home and hot spot networks. Lost or stolen laptops, USB keys, DVDs and smartphones expose the files when security plans neglect disk or file level encryption. Administrators who inappropriately grant broad access rights to people who shouldn’t have them also create vulnerabilities. SharePoint is Microsoft’s file sharing/collaboration/content-and-project-management tool, such as Excel, Visio and Performance Point business services, can create security holes.”]
Source: https://www.csoonline.com/article/2132797/5-places-your-data-goes-to-hide.html