Re: [exim] exim4: headers check syntax?

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Autor: Michael Fischer v. Mollard
Datum:  
To: Marc Haber, exim-users
Alte Treads: Re: [exim] exim4: headers check syntax?
Betreff: Re: [exim] exim4: headers check syntax?


-- On Wednesday, April 05, 2006 17:57:37 +0200 Marc Haber wrote:

> On Wed, 05 Apr 2006 13:57:59 +0200, listrcv <listrcv@???>
>> in exim3, there was an option to check the syntax of mail headers
>> (headers_check_syntax or so).
>>
>> How do I enable that with exim4?
>>
>>
>> Cyrus complains about invalid headers, so I want to check them before
>> such mail is handed over to cyrus. Messages with invalid headers should
>> be rejected before accepting them for not to have a possible exploit for
>> SPAMers.
>
> If you are on Debian, you only need to set the macro
> CHECK_DATA_VERIFY_HEADER_SYNTAX. The code is already there in the DATA
> acl.
>
> The default is off since this might reject legitimate e-mail.
>


Hi,

recently there is a lot of spam containing 8-bit garbage before the message
id.

This stuff is rejected by cyrus ("LMTP error after DATA: 554 5.6.0 Message
contains invalid header"), but accepted by exim. "verify = header_syntax"
won't help, as it only checks the 'syntax of all header lines that can
contain lists of addresses'. What can I do to reject messages with 8-bit
characters in the header (and not in the address or subject header, as this
will reject legitimate mails)?

Michael


--
Michael Fischer v. Mollard, network administration
Heise Zeitschriften Verlag GmbH & Co KG
Helstorfer Straße 7
D-30625 Hannover
Tel: +49 511 5352 477; Email: fvm@???