Max SpamAssassin Size problems

Julian Field mailscanner at ecs.soton.ac.uk
Sat Aug 26 12:32:02 IST 2006


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Desai, Jason wrote:
>>>> do I chop half way through an image?
>>>> do I chop at the end of an image?
>>>> do I carry on for a max of 100 lines of Base64 data or until the end
> 
> [snip]
> 
>> If the code was chopping at the end of an image (ie until it found a 
>> MIME boundary or a blank line.  It would be very easy for someone to 
>> craft an email message that had a starting boundary claiming to be an 
>> image type, but then pumped 100s of Mb without an ending boundary. 
>> There _HAS_ to be a limit to this.
> 
> Agreed.  I don't think the limit should be 100 lines though.  A
> malicious email could be crafted which had a mime boundary claiming to
> be an image, a few normal lines, and then one very long line, MBs long.
> Instead, the limit should probably be a certain number of bytes.
> Perhaps something like 8kB?

Very good thought. I'll measure the length of the next line and only add 
it if that doesn't take me over the 8kb limit.

We're slowly getting there...
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