Malicious Office Startup File Delivered via HTTP

This rule detects the delivery of potentially malicious Microsoft Office startup files (Excel, Word, PowerPoint macro-enabled or binary files) via HTTP. It specifically looks for files with extensions like .xlsb, .xlsm, .docm, .pptm, or .dotm in the HTTP URI and checks for the presence of "vbaProject" content within the file data, indicating the presence of VBA macros which are often used in malicious documents.