[Esd-l] problems with version 1.136 (Mangle MIME type to TEXT/PLAIN, multipart/related inline images)

John D. Hardin jhardin at impsec.org
Tue Nov 5 20:31:36 PST 2002

On Tue, 5 Nov 2002, Peter van Campen wrote:

> John D. Hardin wrote:
> >  Can anybody suggest a MIME type to use here? application/octet-stream
> >  runs the risk of triggering OS magic filetype determination and may
> >  not effectively prevent execution. text/plain apparently will cause
> >  some mailers to do textish things to the file (EOL conversions,
> >  maybe? Line wrap?)
> Maybe something like application/DEFANGEDoctet-stream ?

A possibility. Would you be willing to change it to that locally and
report results?

> Maybe one could have something like:
> 	WARNING: Defanged inline image <DEFANGED_IMG 
> instead of:
> which produces no screen-output in some mailclients.

Hmmm. Maybe.

> Another point: it might be wise for performance-reasons to change
> the /etc/procmailrc to:
> 	#  Only use the sanitizer for mails less than 5MB
> 	:0
> 	* <5000000
> 	{
> 		INCLUDERC=/etc/procmail/html-trap.procmail
> 	}
> Or is it stupid to think that large viruses do not spread?

I won't dictate that. If you feel it's a good idea you're more than
welcome to use it that way.

The virus or worm itself if typically small, but when they grab a
random file from the infected system to use as "camouflage", there's
no telling how large the message will end up.

 John Hardin KA7OHZ    ICQ#15735746    http://www.impsec.org/~jhardin/
 jhardin at impsec.org                        pgpk -a jhardin at impsec.org
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