[Avcheck] avcache announcement

[Ralf Hildebrandt]

Am 14.03.2002 um 18:43:13 +0300 schrieb Michael Tokarev folgendes:

> > The message-id can be forged -- specified by the sender.
> 
> Forged != specified by the sender.  Legitimate senders generates unique
> Message-IDs -- even br0ken outgluck.

But if one is specified neither Postfix nor Qmail throw it away.

> > I don't know how qmail generates (if at all!) message-id's for mail
> > that was intended to be multi-recipient mail.
> 
> Qmail will insert message-id once before sending mail out.  If at all.
> Well, this is interesting point -- qmail may NOT insert missing msgid
> at all.  But for most MUAs, message-id generated at MUA level, not
> by MTA.  I mean MUAs used by "regular" posters, not by some robot etc.

Somebody might be injecting viruses this way:

* Send a legitimate, virus free mail with a correct Message-Id:
* Then send virus infected mails with the same Message-Id:

--> that would suck

> It is very difficult to forge such short-lived msgid.  Well yes, one
> may send a clean message, triggering "clean state on" for this msgid,
> and short after that, send another with the same msgid but infected.

My point exactly.

-- 
Ralf Hildebrandt (Im Auftrag des Referat V A)   Ralf.Hildebrandt@charite.de
Charite Campus Virchow-Klinikum                 Tel.  +49 (0)30-450 570-155
Referat V A - Kommunikationsnetze -             Fax.  +49 (0)30-450 570-916
"Junk mail is war. RFCs do not apply."
                     --  Wietse Venema