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List:       clamav-users
Subject:    [Clamav-users] Re: Compression limit ..... Much too low for me :(
From:       "Mar Matthias Darin" <BDarin () tanaya ! net>
Date:       2004-08-30 3:30:00
Message-ID: E1C1cro-0004Qb-Qj () tanaya ! net
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Have you considered auto-converting the .bmp to a .jpg, and remiming the 
message?  Also, stripping the image and putting it into a temporary web 
link(expires and deletes say after 12 hours)? 

Both might be options to use on your users....  I have many similar things 
I've had to do to keep security high and resources low. 

Lionel Bouton writes: 

> Jason Haar wrote the following on 08/29/2004 11:26 AM : 
> 
>> On Wed, Aug 25, 2004 at 07:42:24AM -0400, Jim Maul wrote:
>>   
>> 
>>> webmasters using BMPs??  I'd leave it at 200, tell him to use jpgs or 
>>> pngs and
>>>     
>>> 
>> 
>> That's a very rough response... I mean - I agree with you - but people 
>> will
>> be people. 
>> 
>> I personally think that compression option should be classified the same 
>> way
>> as the "encrypted zip file" option: disabled by default, and should have
>> more of a description as to why and how you should set it.
>>   
>> 
> 
> Disabling it would probably cause problems on high traffic mail servers if 
> mail bombs come their way... You need disk space to decompress these files 
> and CPU time to decompress and scan. 
> 
>> I disabled it as we had too many people who seem to be sending large BMP
>> files around: instead of the naive, non-IT end-user trying to find some 
>> TOOL
>> to convert their BMP to a JPG, they did the next smart thing and put it 
>> into
>> a ZIP file - thus getting the great compression they were after before
>> e-mailing it off. (I haven't had time to figure out what ratio would be 
>> high
>> enough to allow all such files in, so have disabled instead of setting it
>> higher - which I would actually prefer) 
>> 
>> To blame users for such an action is a bit extreme... 
>> 
>> Not everyone is a Linux user or a Windows programmer/designer - like we 
>> are
>> ;-) 
>> 
>> 
>>   
>> 
> 
> No, but if you tell them BMP is bad (with some explanations like : they 
> reduce the network performance, can be blocked by the destination mail 
> server anyway, need more powerfull computers to process -> money not going 
> into their salary in the end...), block high ratio zips and make sure they 
> all have the software to make GIF/PNG and have a web page on a "knowledge 
> base" web server showing how to save the files in these formats with some 
> screen caps, they will learn. 
> 
> If you don't educate your users you'll end up with more and more problems 
> to solve (regular virus cleaning, server load going through the roof, 
> having to pay for big pipes and expensive servers to cope with their 
> monstruous files and belief that SMTP is a file distribution protocol, 
> ...). 
> 
> Regards,

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