Re: sendmail and starttls failing

From	Jeffrey Walton <noloader@gmail.com>
Newsgroups	linux.debian.user
Subject	Re: sendmail and starttls failing
Date	2024-07-01 00:50 +0200
Message-ID	<IVbwR-6Ml3-3@gated-at.bofh.it> (permalink)
References	<IV585-6Io7-1@gated-at.bofh.it> <IVahr-6LDn-11@gated-at.bofh.it> <IVaU9-6M8t-7@gated-at.bofh.it>
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On Sun, Jun 30, 2024 at 6:08 PM Tim Woodall <debianuser@woodall.me.uk> wrote:
>
> On Sun, 30 Jun 2024, Tim Woodall wrote:
>
> > On Sun, 30 Jun 2024, Michael Grant wrote:
> >
> >> After an update today, sendmail is refusing to accept mail.  I'm
> >> seeing this in the logs:
> >>
> >
> > Hmmm, this update seems to have done a lot of odd things.
> >
>
> root@dirac:~# mail root
> Cc:
> Subject: test cr
> this
> is^Ma test
> .
> root@dirac:~# mailq
> MSP Queue status...
>                  /var/spool/mqueue-client (1 request)
> -----Q-ID----- --Size-- -----Q-Time----- ------------Sender/Recipient-----------
> 45ULV1xk014043       15 Sun Jun 30 22:31 root@dirac.home.woodall.me.uk
>                   (Deferred: 421 4.5.0 Bare carriage return (CR) not allowed)
>                                           root
>                  Total requests: 1
> MTA Queue status...
> /var/spool/mqueue is empty
>                  Total requests: 0
>
> According to this
> https://support.trustwave.com/kb/KnowledgebaseArticle10016.aspx
>
> bare CRs aren't allowed in emails but this has always worked.
>
> I'm only likely to have cron generating emails like this.
>
> Strange that this would have been changed in a stable release. It
> doesn't seem to have been a security update.

New SMTP smuggling attack,
<https://www.openwall.com/lists/oss-security/2023/12/21/6>.

The short of it is, non-conforming emails and sloppy parsing have led
to a litany of problems including mail spoofing. It has been going on
for years, but now things are changing.

Jeff

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sendmail and starttls failing Michael Grant <mgrant@grant.org> - 2024-06-30 18:00 +0200
  Re: sendmail and starttls failing Michael Grant <mgrant@grant.org> - 2024-06-30 18:40 +0200
    Re: sendmail and starttls failing Tim Woodall <debianuser@woodall.me.uk> - 2024-06-30 20:40 +0200
  Re: sendmail and starttls failing Tim Woodall <debianuser@woodall.me.uk> - 2024-06-30 23:30 +0200
    Re: sendmail and starttls failing Michael Grant <mgrant@grant.org> - 2024-06-30 23:40 +0200
      Re: sendmail and starttls failing Tim Woodall <debianuser@woodall.me.uk> - 2024-07-01 00:40 +0200
        Re: sendmail and starttls failing Tim Woodall <debianuser@woodall.me.uk> - 2024-07-01 11:30 +0200
          Re: sendmail and starttls failing Tim Woodall <debianuser@woodall.me.uk> - 2024-07-01 18:40 +0200
    Re: sendmail and starttls failing Tim Woodall <debianuser@woodall.me.uk> - 2024-07-01 00:10 +0200
      Re: sendmail and starttls failing Greg Wooledge <greg@wooledge.org> - 2024-07-01 00:20 +0200
        Re: sendmail and starttls failing Tim Woodall <debianuser@woodall.me.uk> - 2024-07-01 00:30 +0200
          Re: sendmail and starttls failing Mark Fletcher <mark27q1@gmail.com> - 2024-07-01 10:50 +0200
            Re: sendmail and starttls failing Tim Woodall <debianuser@woodall.me.uk> - 2024-07-01 11:20 +0200
            Re: sendmail and starttls failing Greg Wooledge <greg@wooledge.org> - 2024-07-01 13:30 +0200
        Re: sendmail and starttls failing Jeffrey Walton <noloader@gmail.com> - 2024-07-01 00:50 +0200
      Re: sendmail and starttls failing Jeffrey Walton <noloader@gmail.com> - 2024-07-01 00:50 +0200

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