Image scanning - flesh tones

[Paul Welsh]

> Date: Fri, 16 Feb 2007 10:26:49 +0100
> From: "Glenn Steen" <glenn.steen at gmail.com>
> Subject: Re: Image scanning - flesh tones
>
> Um, Paul... Isn't this a bad idea?
> Ok, even if we assume there is little legit images in your corporate
> mail, lets assume someone sends a mail containing a portrait image...
> Maybe in a CV...? Or for that matter the CEOs wife sending him a
> sample of the photo from their vacation and it being labled as
> smut...?
> Sure, images in mail are generally evil, mail should be text only etc
> etc etc. But in reality, hasn't spam as such moved past the pure XXX
> porn sh*t by now?

Sure, this isn't a spam detection thing, it's for stopping unsuitable images
being sent/received by users.  Once they get into the company they get
emailed around the internal mail system and back out again.

I realise it's easy for users to circumvent this filtering by downloading
images from their personal web mail accounts but we currently use
MessageLabs at work and it does block unsuitable images going in or out.

Of course, I have no idea whether it is failing to block lots of unsuitable
images because I am only alerted to the ones it blocks.

I think it does have its uses, but the easiest method is probably to
quarantine image files over a certain size.  I know I can quarantine images
but not sure about filtering on file type + size with MailScanner.  It will
be trial and error, obviously.

Naturally, the costs of MailScanner vs MessageLabs don't bear comparison.
The former is GBP43 per user per year whereas MailScanner is the cost of 2
servers (one for redundancy) plus a commercial AV scanner.  We have a Sophos
site licence so the commercial AV licence is covered.  I'd add Clam too.
The only downside apart from the image scanning and the time it costs to
setup and maintain is the slight overhead of spam and virus infected
messages using up our leased line bandwidth (such messages don't make it
down our leased line with MessageLabs).  No contest.