[Asrg] where the message originated

[Alessandro Vesely]

Rich Kulawiec wrote:
> On Mon, Jan 12, 2009 at 12:42:59PM -0500, der Mouse wrote:
>> 
>> - Malware goes out, addressed to A, (forged) envelope-from B.  Sending
>>    channel ends up emitting it from a normal MTA, M.
>> 
>> - A's MX host rejects it at SMTP time.
>> 
>> - M generates and sends a bounce to B.
>> 
>> - B receives bounce with embedded malware.  Somehow - perhaps B's MUA
>>    aggressively looks for and executes live content; perhaps B clicks
>>    on the wrong thing; perhaps something else - this ends up with a
>>    malware infestation on B's machine.  (Cue xkcd #350.)
>> 
>> If A's MX host had silently swallowed the mail, nothing would have
>> happened to B - or, at least, not on account of this message.
> 
> Ah, gotcha.  I agree that silently swallowing the message might have
> spared B a possible infection, but I'm reluctant to blame A's MX for
> this: it didn't originate, accept or transfer the malware-laden message.

A's MX knows that M lacks effective anti-virus filtering. Hence, 
through inaction, it allowed a human being to come to harm. That 
obviously breaks the first law.