This article applies to:

• Trustwave MailMarshal (SEG)
• Trustwave ECM/MailMarshal Exchange
• Image Analyzer

Question:

• What image types are scanned by Image Analyzer?
• What are the Image Analyzer return values in message logs?

Information:

Image Analyzer is an optional module for current versions of SEG and ECM, that inspects image content.

• In MailMarshal 10.1.0 and above, Image Analyzer can detect a number of types of images including pornography and other potentially inappropriate or time-wasting categories.
• In earlier releases, Image Analyzer detects potentially inappropriate (pornographic) images.

When you configure an image analysis rule condition, MailMarshal invokes Image Analyzer to check all files of type IMAGE or Binary Unknown.

Image Analyzer actually checks files of the following types:

BMP, DIB, JPEG, JPG, JPE, J2K, JBG, JPC, PNG, PBM, PGM, PPM, SR, RAS, TIFF, TIF, GIF, TGA, WMF, PGX, PNM, RAS

• If the file is not one of the supported types, the MailMarshal rule condition will return "false" (not triggered).
• If the file is one of the supported types, the MailMarshal rule condition depends on the results returned by Image Analyzer.

Notes:

In the MailMarshal message logs, the detailed Image Analyzer result is listed. 

Sample results (10.0 and below) are as follows:

• ImageAnalysis: Good(0) 16ms - Coffee Bean.bmp
• ImageAnalysis: Inappropriate(81) 500ms - porn.jpg
• ImageAnalysis: Unsupported file(-2) 0ms - MailMarshal.ico

Sample results (10.1 and above) are as follows:

• ImageAnalysis: Does not match category 7174 (0) 1735ms - DC10.jpg
• ImageAnalysis: Matches category 5519 (99) 62ms - DC10.jpg
• ImageAnalysis: Image is not valid [C:\Program Files\Trustwave\Secure Email Gateway\Unpacking\T3\U2\Trustwave.ico]

Depending on the specific version of MailMarshal/Image Analyzer used, files of unsupported types may be logged as "good(0)", "Unsupported file(-2)", or "Image is not valid". In all such cases the MailMarshal rule condition will return "false."