I need to make sure the report is complete but concise. Maybe include timestamps, file paths, hashes (MD5, SHA1, SHA256) for verification. Also, if possible, check the file's reputation scores from online databases.

I should also think about how to present the findings clearly. For example, if scanning with VirusTotal shows no positives, that's important. If there are positives, list them. Also, mention any known malware families that match the file's characteristics. Maybe use a malware analysis report template for structure.

So, in the analysis, I'd note the file contents, check each file's properties, MIME types, file headers to see if they match the expected type. Also, look for macros if there are .doc or .xls files inside. Maybe if there's a script or payload, check for obfuscation techniques or encoded commands.

I should structure the report with an executive summary, detailed analysis, findings, and a conclusion. Make sure to include both the steps taken and the results. If there's no clear threat, still document that. Maybe mention that without further analysis in a secure environment, the risk can't be fully assessed. Also, note that opening attachments from unknown sources is a best practice to avoid.