Clueless anti-virus products/vendors (was Re: Sober)

Edward B. Dreger eddy+public+spam at noc.everquick.net
Wed Dec 7 21:35:07 UTC 2005


DO> Date: Tue, 6 Dec 2005 16:26:16 -0800
DO> From: Douglas Otis

DO> I know of no cases where a malware related DSN would be generated by our

Good.


DO> products, nevertheless, DSNs are not Unsolicited Bulk Email.

Huh?  I get NDRs for mail that "I" sent.  I do not want those NDRs.  I 
did not request those NDRs.  Those NDRs are not in response to a message 
I sent.

I do not want backscatter NDR notices.  I frankly don't care that 
WhizBangAV caught WormOfTheWeek on Susie Smith's corporate mail in 
Argentina from Billy Boo's PC in China... just because my address 
happened to be the subject of a joe jobbing worm.

Really.  Even reading and posting to NANOG is more important. ;-)


DO> Not all email is rejected within the SMTP session.  You are changing
DO> requirements for recipients that scan incoming messages for malware.  Fault
DO> them for returning content or not including a null bounce-address.  No one
DO> can guarantee an email-address within the bounce-address is valid,

Perhaps DSNs should be sent to the original recipient, not the purported 
sender.  RFC-compliant?  No.  Ridiculous?  Less so than pestering a 
random third party.  Let the intended recipient communicate OOB or 
manually if needed.


DO> furthermore a DSN could be desired even for cases where an authorization

When auth fails, one knows *right then* c/o an SMTP reject.  No bounce 
is necessary.


DO> scheme fails.  Why create corner cases?

The corner case is that a virus _might_ actually have a realistic "From" 
address. :-)


DO> DomainKeys and Sender-ID can not validate the bounce-address or the DSN.
DO> Even with an SPF failure, a DSN should still be sent, as SPF fails in

If you receive mail with

	From: <eddy at everquick.net>

coming from 10.10.10.10, and everquick.net SPF records indicate that IP 
address is bogus, how can you possibly justify "that mail may indeed 
have come from how it's apparently addressed"?  Doubly so when a virus 
is known to spoof "from" addresses!

Saying a DSN should be sent is just untenable.


DO> several scenarios, and false positives are never 0%.  BATV offers a
DO> unilateral option that can effectively discard spoofed bounce-addresses.
DO> When the AV software provides the DSN with a null bounce-address, BATV works
DO> as advertised.


Eddy
--
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