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Posted to users@spamassassin.apache.org by Per Jessen <pe...@computer.org> on 2010/05/31 14:12:54 UTC

leading blanks on From:addr prevents e.g. blacklisting from working

I have just this morning come across an interesting issue (SA 3.2.5). I
was trying to blacklist a From: address using 'blacklist_from', but it
wasn't working.  I took a closer look at the email, and noticed:

From: "something or other" < mailing@example.com>

The single leading space in the address part is the issue.  Before I go
and open a bugreport (I suspect the same issue may be present in the
3.3 series), I just wanted to see if this just might be a known issue?


/Per Jessen, Zürich


Re: leading blanks on From:addr prevents e.g. blacklisting from working

Posted by Per Jessen <pe...@computer.org>.
Benny Pedersen wrote:

> On Mon 31 May 2010 02:12:54 PM CEST, Per Jessen wrote
>> From: "something or other" < mailing@example.com>
> 
> mailzu / amavisd-new also using the From: header, here i am just
> unsure if this is just on web it displays the From: addr, might be
> related or not
> 
> anyway why not blacklist_from envelope_sender ?

Because it is a mass-emailing company.


/Per Jessen, Zürich


Re: leading blanks on From:addr prevents e.g. blacklisting from working

Posted by Benny Pedersen <me...@junc.org>.
On Mon 31 May 2010 02:12:54 PM CEST, Per Jessen wrote
> From: "something or other" < mailing@example.com>

mailzu / amavisd-new also using the From: header, here i am just  
unsure if this is just on web it displays the From: addr, might be  
related or not

anyway why not blacklist_from envelope_sender ?

in postfix this is Return-Path, is there a space there ?

spamassassin should not be idiotic checking the wrong header where  
anything not authed can be writed

is there any mta that will accept space in mail-from ?

-- 
xpoint http://www.unicom.com/pw/reply-to-harmful.html


Re: leading blanks on From:addr prevents e.g. blacklisting from working

Posted by Per Jessen <pe...@computer.org>.
Michael Scheidell wrote:

> On 5/31/10 8:12 AM, Per Jessen wrote:
>> I have just this morning come across an interesting issue (SA 3.2.5).
>> I was trying to blacklist a From: address using 'blacklist_from', but
>> it wasn't working.  I took a closer look at the email, and noticed:
>>
>> From: "something or other"<  mailing@example.com>
>>    
> Interesting.. the addr part of the email address would be invalid by
> RFC standards (the addr part cannot start with a space)

Correct. 

> just use your MTA to block invalid addresses at the gateway. 

This is _only_ the From: in the header - AFAIK, the MTA (postfix)
doesn't check or even care much about it. 

> with the MTA blocking it, the sender (if they are really the sender
> and not a bot) will get the NDR without the issue of backscatter to
> (what address would you bounce it to?  %20mailing@example.com  ?

No, the envelope address is a genuine bounce-<something> from a
mass-emailing service. 

> is this in the header from, the envelope from or both?  postfix strips
> the %20 (space), and changes the envelope (return-path) to
> mailing@example.com so is this just in the header from?

Yup. 


/Per Jessen, Zürich


Re: leading blanks on From:addr prevents e.g. blacklisting from working

Posted by Mark Martinec <Ma...@ijs.si>.
On Monday 31 May 2010 16:13:24 Per Jessen wrote:
> Michael Scheidell wrote:
> > interesting that sa 3.3.1 only scores this as a +1 score.  must mean
> > it doesn't match a lot of spam vs ham.
> 
> Must also mean that it is not an issue in SA 3.3, good.  In my case, the
> email is not spam as such, I suspect the leading blank is just a
> programming error.

Looks fine with 3.3.1, seems the leading space is stripped and blacklisting 
works.

  Mark

Re: leading blanks on From:addr prevents e.g. blacklisting from working

Posted by Per Jessen <pe...@computer.org>.
Michael Scheidell wrote:

> interesting that sa 3.3.1 only scores this as a +1 score.  must mean
> it doesn't match a lot of spam vs ham.

Must also mean that it is not an issue in SA 3.3, good.  In my case, the
email is not spam as such, I suspect the leading blank is just a
programming error. 


/Per Jessen, Zürich


Re: leading blanks on From:addr prevents e.g. blacklisting from working

Posted by Michael Scheidell <sc...@secnap.net>.
On 5/31/10 8:39 AM, Michael Scheidell wrote:
> On 5/31/10 8:12 AM, Per Jessen wrote:
>> I have just this morning come across an interesting issue (SA 3.2.5). I
>> was trying to blacklist a From: address using 'blacklist_from', but it
>> wasn't working.  I took a closer look at the email, and noticed:
>>
>> From: "something or other"<  mailing@example.com>
> Interesting.. the addr part of the email address would be invalid by 
> RFC standards (the addr part cannot start with a space)
> just use your MTA to block invalid addresses at the gateway.  with the 
> MTA blocking it, the sender (if they are really the sender and not a 
> bot) will get the NDR without the issue of backscatter to (what 
> address would you bounce it to?  %20mailing@example.com  ?
>
> is this in the header from, the envelope from or both?  postfix strips 
> the %20 (space), and changes the envelope (return-path) to  
> mailing@example.com so is this just in the header from?
>
interesting that sa 3.3.1 only scores this as a +1 score.  must mean it 
doesn't match a lot of spam vs ham.

FROM_WSP_LEAD

(the 1+ score is a default based on not having a score value listed anywhere)

grep FROM_WSP_LEAD /var/db/spamassassin/3.003001/updates_spamassassin_org/* /usr/local/etc/mail/spamassassin//*.cf
/var/db/spamassassin/3.003001/updates_spamassassin_org/72_active.cf:##{ FROM_WSP_LEAD
/var/db/spamassassin/3.003001/updates_spamassassin_org/72_active.cf:header   FROM_WSP_LEAD 	From:raw =~ /<  \s+ [^>\s] [^>]*>  [^<>]* \z/xm
/var/db/spamassassin/3.003001/updates_spamassassin_org/72_active.cf:describe FROM_WSP_LEAD	Leading whitespace after '<' in From header field
/var/db/spamassassin/3.003001/updates_spamassassin_org/72_active.cf:##} FROM_WSP_LEAD





> my understanding of SA (from a while back) is that it will 
> blacklist_from based on header from, envelope from and/or sender from, 
> so if that is so, it should have worked.
>
>
>


-- 
Michael Scheidell, CTO
Phone: 561-999-5000, x 1259
 > *| *SECNAP Network Security Corporation

    * Certified SNORT Integrator
    * 2008-9 Hot Company Award Winner, World Executive Alliance
    * Five-Star Partner Program 2009, VARBusiness
    * Best Anti-Spam Product 2008, Network Products Guide
    * King of Spam Filters, SC Magazine 2008

______________________________________________________________________
This email has been scanned and certified safe by SpammerTrap(r). 
For Information please see http://www.secnap.com/products/spammertrap/
______________________________________________________________________  

Re: leading blanks on From:addr prevents e.g. blacklisting from working

Posted by Michael Scheidell <sc...@secnap.net>.
On 5/31/10 8:12 AM, Per Jessen wrote:
> I have just this morning come across an interesting issue (SA 3.2.5). I
> was trying to blacklist a From: address using 'blacklist_from', but it
> wasn't working.  I took a closer look at the email, and noticed:
>
> From: "something or other"<  mailing@example.com>
>    
Interesting.. the addr part of the email address would be invalid by RFC 
standards (the addr part cannot start with a space)
just use your MTA to block invalid addresses at the gateway.  with the 
MTA blocking it, the sender (if they are really the sender and not a 
bot) will get the NDR without the issue of backscatter to (what address 
would you bounce it to?  %20mailing@example.com  ?

is this in the header from, the envelope from or both?  postfix strips 
the %20 (space), and changes the envelope (return-path) to  
mailing@example.com so is this just in the header from?

my understanding of SA (from a while back) is that it will 
blacklist_from based on header from, envelope from and/or sender from, 
so if that is so, it should have worked.



-- 
Michael Scheidell, CTO
Phone: 561-999-5000, x 1259
 > *| *SECNAP Network Security Corporation

    * Certified SNORT Integrator
    * 2008-9 Hot Company Award Winner, World Executive Alliance
    * Five-Star Partner Program 2009, VARBusiness
    * Best Anti-Spam Product 2008, Network Products Guide
    * King of Spam Filters, SC Magazine 2008


______________________________________________________________________
This email has been scanned and certified safe by SpammerTrap(r). 
For Information please see http://www.secnap.com/products/spammertrap/
______________________________________________________________________