nanog mailing list archives

Re: Transparent hijacking of SMTP submission...


From: Suresh Ramasubramanian <ops.lists () gmail com>
Date: Fri, 28 Nov 2014 05:40:03 +0530

Yes. Till that hotspots IP space gets blackholed by a major freemail
because of all the nigerians and hijacked devices emitting bot traffic
through stolen auth credentials.

There's other ways to stop this but they take actual hard work and rather
more gear than a rusted up old asa you pull out of your closet as like as
not.
 On Nov 28, 2014 2:10 AM, "Mark Andrews" <marka () isc org> wrote:


Which is why your MTA should always be setup to require the use of
STARTTLS.  Additionally the CERT presented should also match the
name of the server.

There is absolutely no reason for a ISP / hotspot to inspect
submission traffic.  The "stopping spam" argument doesn't wash with
submission.

Mark

In message <54778167.7080808 () bogus com>, joel jaeggli writes:

I don't see this in my home market, but I do see it in someone else's...
I kind of expect this for port 25 but...

J@mb-aye:~$telnet 147.28.0.81 587
Trying 147.28.0.81...
Connected to nagasaki.bogus.com.
Escape character is '^]'.
220 nagasaki.bogus.com ESMTP Sendmail 8.14.9/8.14.9; Thu, 27 Nov 2014
19:17:44 GMT
ehlo bogus.com
250-nagasaki.bogus.com Hello XXXXXXXXXXXXXXX.wa.comcast.net
[XXX.XXX.XXX.XXX], pleased to meet you
250 ENHANCEDSTATUSCODES

J@mb-aye:~$telnet 2001:418:1::81 587
Trying 2001:418:1::81...
Connected to nagasaki.bogus.com.
Escape character is '^]'.
220 nagasaki.bogus.com ESMTP Sendmail 8.14.9/8.14.9; Thu, 27 Nov 2014
19:18:33 GMT
ehlo bogus.com
250-nagasaki.bogus.com Hello
[IPv6:2601:7:2380:XXXX:XXXX:XXXX:c1ae:7d73], pleased to meet you
250-ENHANCEDSTATUSCODES
250-PIPELINING
250-8BITMIME
250-SIZE
250-DSN
250-AUTH DIGEST-MD5 CRAM-MD5 LOGIN
250-STARTTLS
250-DELIVERBY
250 HELP

that's essentially a downgrade attack on my ability to use encryption
which seems to be in pretty poor taste frankly.
--
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: marka () isc org



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