Multipurpose Internet Mail Extensions (MIME) is a standard that specifies how email messages are formatted. MIME allows email messages to contain attachments of several file types, which can be referred to as MIME content subtypes. These subtypes include multimedia files, such as MP3, and common application files, such as Microsoft Word.
Malicious code can reside in many types of email attachments. Trend Micro strongly recommends enabling MIME-subtype type filtering when you configure a message attachment filter. Because an email message with an attachment contains MIME content information in the email header, InterScan™ Messaging Security Appliance (IMSA) can identify the attachment and filter it if necessary.
If an attachment is of a certain MIME subtype, you can:
Automatically strip the attachment and append a notification to the email message
Perform a filter action on the email message
IMSA can scan for the following MIME content subtypes:
Audio files—WAV, MP3, MIDI
Documents—Microsoft Word, Excel, PowerPoint, Adobe PDF, RTF
Image files—JPEG, GIF, BMP, TIF/TIFF
Video files—MPEG, MSVideo, Quicktime
You can also define your own MIME content subtypes to filter.
See also: