MIME Type Mappings

Overview

MIME type mappings define the relationship between file extensions and their expected MIME types. The scan engine uses these mappings to verify that files are what they claim to be — a critical defense against file extension spoofing attacks.

Accessing MIME Type Mappings

1. Go to Settings → File Scan
2. Scroll to Advanced Configuration
3. Click the MIME-Type to Extensions Mappings tab

Why MIME Type Mappings Matter

Attackers often disguise malicious files by changing their extension. For example:

• A .exe file renamed to .pdf
• A .html file renamed to .jpg

When MIME type checking is enabled (see Scan Configuration), the engine compares the file's actual MIME type against what the extension declares. If there's a mismatch, the file can be blocked.

Managing Mappings

Each mapping row includes an extension and a MIME type.

1. Add: Click Add New, enter extension and MIME type, click Save in the modal, then click the main Save.
2. Edit: Select a mapping, update values, then click Save.
3. Delete: Click the Delete icon for a mapping, confirm the dialog, then click Save.

Common MIME Type Examples