topic Re: hiding sendmail version in Operating System - HP-UX

hiding sendmail version

Fred Martin_1 — Fri, 27 Dec 2002 15:30:40 GMT

I believe there is a way to hide the sendmail version from outgoing mail, but I can't locate any information. I'm running HP-UX 11.0 with sendmail 8.9.3 (PHNE_24419). Does anyone know how I can change the version info to a given string of characters, or maybe just turn it off?

Re: hiding sendmail version

Robert-Jan Goossens — Fri, 27 Dec 2002 15:40:39 GMT

Take a look at this one,

http://info.nixhosting.net/sendmail/

search inside the page for hiding.

Hope it helps,

Robert-Jan.

Re: hiding sendmail version

Fred Martin_1 — Fri, 27 Dec 2002 15:47:54 GMT

In the meantime I found this in the cf file:

DZ8.9.3

and changed it to:

DZtest

Now this is displayed:

.... (8.9.3(PHNE_24419)/test) ...

So that's not entirely it.

I'll look at that info, thanks.
Fred

Re: hiding sendmail version

Fred Martin_1 — Fri, 27 Dec 2002 16:00:34 GMT

FYI also found this in the cf:

O SmtpGreetingMessage=$j Sendmail $v/$Z; $b

But I don't see the word "Sendmail" in any outgoing headers so I haven't solved it yet.

The article has some interesting information thanks.
Fred

Re: hiding sendmail version

Fred Martin_1 — Fri, 27 Dec 2002 17:44:33 GMT

I think I found what I was looking for - in the sendmail.cf file, at least for my version of sendmail....

These are the lines in the cf file that display version information....

In the smtp login dialog:

O SmtpGreetingMessage=$j Sendmail $v/$Z; $b

In the headers of emails:

HReceived: $?sfrom $s $.$?_($?s$|from $.$_)
$.by $j ($v/$Z)$?r with $r$. id $i$?u
for $u; $|;
$.$b

...so it looks like the values $v and $Z control what is displayed.

$Z is set with the line:

DZ8.9.3

I'm not sure where $v is set - if anyone knows where to change this value, let me know.

I suppose I could change the 'O Smtp' and 'HReceived:' lines but I'm not sure that's the correct way to do it.

Re: hiding sendmail version

Jeff Schussele — Fri, 27 Dec 2002 19:03:42 GMT

Hi Fred,

Others have you on track for your primary question, but another thing you should do to harden SendMail is to disable verification & username expansion.
Two ways to do this in the sendmail.cf file:
A) O PrivacyOptions=goaway #easiest
B) O PrivacyOptions=noexpn,novrfy #most granular

If these are enabled - and they are by default - hackers can verify account names on the system.

Rgds,
Jeff