[Discuss] e-mails with a "from" address that is of some concern

[Alan W. Irwin]

On 2014-04-19 17:50-0500 mskala at ansuz.sooke.bc.ca wrote:

> On Sat, 19 Apr 2014, Alan W. Irwin wrote:
>> We have recently started seeing spam that purports to be sent from our
>> own computer, e.g., <somename>@<FQDN> where FQDN is the fully
>> qualified (and quite unique) local name I happen to give my computer in
>> /etc/hosts.
>
> Is it possible that the mail is coming in with no FQDN - for instance, as
> <somename> with no @ part, or <somename>@<ip address> - and then your
> mailer is assuming that that is local and filling in the FQDN?
>
>> As far as I know, I have never leaked that fully qualified name out in
>> e-mail or anywhere else.
>
> Does the box that has this name ever send mail?  If so, the name could
> have leaked out via a Received: header.  Does it ever receive mail?  If
> so, the name may have appeared in the receiving mailer's HELO or EHLO
> identification.

I keep a copy of all e-mail sent.  The name was not leaked via a
Received: header, but I just now discovered a few cases of e-mail over
the years that leaked the name with a References: header (from
the Debian reportbug application).  But there are certainly no such
recent leaks.

> In any case, is this actually a problem?

Probably not, but if I can find no credible explanation, then one
nasty possibility left is the spammers somehow have access to my
/etc/hosts file (i.e., they own the box).

Alan

__________________________
Alan W. Irwin

Astronomical research affiliation with Department of Physics and Astronomy,
University of Victoria (astrowww.phys.uvic.ca).

Programming affiliations with the FreeEOS equation-of-state
implementation for stellar interiors (freeeos.sf.net); the Time
Ephemerides project (timeephem.sf.net); PLplot scientific plotting
software package (plplot.sf.net); the libLASi project
(unifont.org/lasi); the Loads of Linux Links project (loll.sf.net);
and the Linux Brochure Project (lbproject.sf.net).
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