XLM macros Up to and including Microsoft Excel 4.0, a macro format called XLM was available. XLM macros predate the VBA macros that are more common with modern Microsoft Office systems, however current Microsoft Office versions still support XLM macros.



SYLK and XLM macros



XLM macros can be incorporated into SYLK files, as outlined by Outflank. Macros in the SYLK format are problematic in that Microsoft Office does not open in Protected View to help protect users. This means that users may be a single click away from arbitrary code execution via a document that originated from the internet.



SYLK and XLM macros with Microsoft Office for Mac



It has been reported that Office 2011 for Mac fails to warn users before opening SYLK files that contain XLM macros. According to this post, Microsoft has reported that Office 2016 and Office 2019 for Mac properly prompt the user before executing XLM macros in SYLK files.



The Problem



If Office for the Mac has been configured to use the "Disable all macros without notification" feature, XLM macros in SYLK files are executed without prompting the user.