.msg file detected as Malware by defender?

Question

Why Microsoft Defender always categorized .msg file as Malware (most of the times, when it is found in SharePoint it verify as Clean)

Answer 1

Microsoft Defender may categorize .msg files as malware due to the potential for these files to contain malicious content. .msg files are Microsoft Outlook email message files, and they can include attachments or embedded content that may be harmful. If a .msg file is detected in SharePoint, it could be flagged based on its contents or behavior, especially if it exhibits characteristics commonly associated with malware.

Defender's scanning processes are designed to identify and mitigate threats, and if a .msg file is suspected of containing malware or if it matches certain threat signatures, it may be categorized as such. Additionally, Defender employs smart heuristics and threat signals to identify potentially malicious files, which may lead to the frequent categorization of .msg files as malware.

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References:

• Safe Attachments for SharePoint, OneDrive, and Microsoft Teams
• Antimalware protection in Exchange Server