[Mimedefang] Image blocking idea

[Martin Blapp]

Hi,

> On a different note concerning images, what about an email filter logging the
> possibility of the images containing hidden data (i.e. Steganography test).

I already log possible text (I count alphanummeric chars in the ocr output)

+header		SPAMPIC_ALPHA_1		OCR-Output =~ /OCRTEXT: more than alpha1 chars found/
+describe	SPAMPIC_ALPHA_1		Image contains many alphanumeric chars
+score		SPAMPIC_ALPHA_1		0.500
+
+header		SPAMPIC_ALPHA_2		OCR-Output =~ /OCRTEXT: more than alpha2 chars found/
+describe	SPAMPIC_ALPHA_2		Image contains many alphanumeric chars
+score		SPAMPIC_ALPHA_2		1.000
+
+header		SPAMPIC_ALPHA_3		OCR-Output =~ /OCRTEXT: more than alpha3 chars found/
+describe	SPAMPIC_ALPHA_3		Image contains many alphanumeric chars
+score		SPAMPIC_ALPHA_3		1.500

You could now do a statistic analytic to see if the chars match any language 
specific char occurance to see if its really text.

Martin