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Posted to users@spamassassin.apache.org by "John D. Hardin" <jh...@impsec.org> on 2006/06/26 06:14:48 UTC
Re: [SPAM] Examples of Received Headers
On Sun, 25 Jun 2006, Jim Hermann - UUN Hostmaster wrote:
> Here are examples of the Received Headers for the type of spam
> that are being sent with forged email addresses for a domain that
> I host.
The Received headers in spams cannot be trusted, except for the
Received headers put in by relays run by *you* or someone you trust.
Received headers are trivially easy to forge and cary very little
useful information in spams.
> These at the last 10 bounced messages that I received, so it is
> fairly representative.
It's not clear from your description whether these Received headers
are from the spams or from the bounces.
> I send complaints to the abuse email address listed in the WHOIS
> record for this IP Address.
As I said above, you can't trust a Received header unless your server
put it there.
If you are responding to the earliest Received header in a spam, then
you are at best wasting your time, at worst confirming the validity of
your email address.
> Do you think that these are victims of some sort that their ISP
> would want to help?
You need to contact the ISP that sent you the bounce message, NOT the
ISP that sent the spam. The ISP that the spammer targeted is the one
you want to talk into implementing SPF checks.
--
John Hardin KA7OHZ ICQ#15735746 http://www.impsec.org/~jhardin/
jhardin@impsec.org FALaholic #11174 pgpk -a jhardin@impsec.org
key: 0xB8732E79 - 2D8C 34F4 6411 F507 136C AF76 D822 E6E6 B873 2E79
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Apparently the Bush/Rove idea of being a "fiscal conservative" is
to spend money like there's no tomorrow, run up huge deficits, and
pray the Rapture happens before the bills come due.
-- atul666 in Y! SCOX forum
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Re: [SPAM] Examples of Received Headers
Posted by Graham Murray <gr...@gmurray.org.uk>.
"Jim Hermann - UUN Hostmaster" <ho...@uuism.net> writes:
> SPF is not enough. It does not eliminate the zombie or spambot.
It is if you set your SPF record to allow your mailer(s) and hard fail
on all others *and* the recipient of the forged email checks against
SPF. The problems come when recipients do not check (and act on) SPF
even when you have defined a 'tight' SPF record.
RE: Examples of Received Headers
Posted by "John D. Hardin" <jh...@impsec.org>.
On Sun, 25 Jun 2006, Jim Hermann - UUN Hostmaster wrote:
> > On Sun, 25 Jun 2006, Jim Hermann - UUN Hostmaster wrote:
> >
> > > Here are examples of the Received Headers for the type of spam
> > > that are being sent with forged email addresses for a domain that
> > > I host.
> >
> > The Received headers in spams cannot be trusted, except for the
> > Received headers put in by relays run by *you* or someone you trust.
> > Received headers are trivially easy to forge and cary very little
> > useful information in spams.
>
> These are Received Headers provided by the ISP that sent me the
> bounce message, not because of spam, but because the recipient did
> not exist. They put the Original Spam Full Headers in the message
> that they sent to me.
Erm. Again, I'm not clear on what you provided examples of.
Were the Received headers from the message headers of the bounce
itself? If so, contact the ISP that you received the message from and
ask them to implement SPF checks.
Were the Received headers from the *body* of the bounce, where the
other ISP put a copy of the spam headers? If so, you can't trust them
and for the most part trying to parse them is a waste of time.
> If I can trust that my server identified the last server and the
> last server was the recipient server, then I think I can trust
> that they sent me the Full Headers as they received them. Yes, I
> know that the prior Received Headers could be forged.
The headers as they received them are also likely forged.
You *might* be able to trust the Received header that their mail relay
put in, which could tell you from where they received the email.
Beyond that, they are subject to forgery.
> I don't think that these spambots are bothering to try to forge
> the Received Headers. Usually the first two Received Headers have
> IP Addresses assigned to the same ISP.
>
> SPF is not enough. It does not eliminate the zombie or spambot.
No, but it does fairly well what it is intended to do: eliminate
forgeries.
SPF is *not* an anti-spam tool. It is an anti-forgery tool.
I agree, though, that it should be part of a larger set of tools.
--
John Hardin KA7OHZ ICQ#15735746 http://www.impsec.org/~jhardin/
jhardin@impsec.org FALaholic #11174 pgpk -a jhardin@impsec.org
key: 0xB8732E79 - 2D8C 34F4 6411 F507 136C AF76 D822 E6E6 B873 2E79
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RE: [SPAM] Examples of Received Headers
Posted by Jim Hermann - UUN Hostmaster <ho...@uuism.net>.
> On Sun, 25 Jun 2006, Jim Hermann - UUN Hostmaster wrote:
>
> > Here are examples of the Received Headers for the type of spam
> > that are being sent with forged email addresses for a domain that
> > I host.
>
> The Received headers in spams cannot be trusted, except for the
> Received headers put in by relays run by *you* or someone you trust.
> Received headers are trivially easy to forge and cary very little
> useful information in spams.
These are Received Headers provided by the ISP that sent me the bounce
message, not because of spam, but because the recipient did not exist. They
put the Original Spam Full Headers in the message that they sent to me.
If I can trust that my server identified the last server and the last server
was the recipient server, then I think I can trust that they sent me the
Full Headers as they received them. Yes, I know that the prior Received
Headers could be forged.
I don't think that these spambots are bothering to try to forge the Received
Headers. Usually the first two Received Headers have IP Addresses assigned
to the same ISP.
SPF is not enough. It does not eliminate the zombie or spambot.
Jim