[Tutor] parsing email

[Karl Pflästerer]

On 29 Jan 2004, Michael Janssen <- Janssen at rz.uni-frankfurt.de wrote:

> On Wed, 28 Jan 2004, Mike Hansen wrote:

>> Thanks for the reply. I'm told they are text files with each message
>> having its own text file.

> when each eMail is on a single file - why not just run a virus scanner
> about them? The virus scanner can savely delete all virus mails.

A virus scanner can easily be broken by unfriendly senders; e.g. if you
send an e-mail with a zip attachment the scanner has to unpack the
attachment.  If you zipped a bigggggg file (some GB) of only zeros you
have a small and nice zip file which if unzipped stops your machine (to
make it perfekt you need a hex editor to change the header of the zip
file so the real size can't be seen).  Or use bzip2.  Google for 42.zip.
Furthermore a virus scanner has to know the pattern of the virus.  So a
virus scanner gives you a false feeling of security.  And you might not
only want to search for virus files but for every sort of UCE or UBE.



   Karl
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