Wietse Venema via Postfix-users:
> Damian via Postfix-users:
> > > The recommended settings are:                                             
> > >                                                                           
> > >                                                                           
> > >                                                                         
> > > 
> > >  # Optionally disconnect remote SMTP clients that send bare newlines,
> > >  # but allow local clients with non-standard SMTP implementations
> > >  # such as netcat, fax machines, or load balancer health checks.
> > >  #
> > >  smtpd_forbid_bare_newline = yes
> > >  smtpd_forbid_bare_newline_exclusions = $mynetworks
> > 
> > 
> > The test tool [1] revealed that my 3.7.9 Postfix using 
> > `smtpd_forbid_bare_newline = yes` admits smuggling for the `\r\n.\n` case. 
> > One still needs `smtpd_data_restrictions = reject_unauth_pipelining` to 
> > close that one as well.
> > 
> > [1] https://github.com/The-Login/SMTP-Smuggling-Tools.git
> 
> Postfix with the fix does not treat \r\n.\n as an End-of-DATA.
> 
> Nor does it treat \r\n.\r as End-of-DATA. 
> 
> When I send message content with \r\n.\r, it arrives as message
> content with \r at the beginning of a line. It does not terminate
> DATA and does not enable smuggling.

Just for kicks,  I tried \r\n.\r and it would not even smuggle with
unpatched Postfix (smtpd_forbid_bare_newline = no).

        Wietse

> Sent as one SMTP mail transaction:
> 
>     [omitted: ehlo, mail from, rcpt to, data]
>     non-smuggled text ending in\r\n
>     .\r
>     mail from:<>\r\n
>     rcpt to:<recipient>\r\n
>     data\r\n
>     other text lines ending in\r\n
>     .\r\n
> 
> Delivered by Postfix as one email messages with SMTP commands in the middle:
> 
>     non-smuggled text
>     \rmail from:<>    
>     rcpt to:<recipient>
>     data
>     [other text]
> 
> In other words, I need to see proff in the form of a PCAP file and
> NON-VERBOSE logging, or it did not happen.
> 
>       Wietse
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