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Posted to users@spamassassin.apache.org by Jeff Koch <je...@intersessions.com> on 2004/12/14 19:09:29 UTC

blank subject and contents

Hi:

We're getting hit with a lot of emails with blank subject lines and blank 
contents. Could be some kind of address verification robot. Is SA supposed 
to filter these? If not, does anyone have some custom rules that would do it?



Best Regards,

Jeff Koch 



Re: blank subject and contents

Posted by Theo Van Dinter <fe...@kluge.net>.
On Wed, Feb 02, 2005 at 06:17:57PM -0800, Robert Menschel wrote:
> An S/O of 0.812 for SARE_EMPTY_SUBJ_BODY is maybe worth a point or so,
> but it's not a strong enough indicator of spam to be worth much.

Ewww!  (I'd just delete things around 0.8...)

It doesn't hit a ton, but there is a rule in 3.1 to catch these:

OVERALL%   SPAM%     HAM%     S/O    RANK   SCORE  NAME
 190919   170010    20909    0.890   0.00    0.00  (all messages)
  1.299   1.4587   0.0000    1.000   0.82    1.00  EMPTY_MESSAGE

It requires code from 3.1, so it's not any use in 3.0, but ...  FYI. :)

-- 
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"In the universe, great acts are made up of small deeds." - Lao Tzu

Re: blank subject and contents

Posted by Robert Menschel <Ro...@Menschel.net>.
Hello Jeff,

Tuesday, December 14, 2004, 10:09:29 AM, you wrote:

JK> We're getting hit with a lot of emails with blank subject lines and blank
JK> contents. Could be some kind of address verification robot. Is SA supposed
JK> to filter these? If not, does anyone have some custom rules that would do it?

I finally got around to testing these rules:

header    SARE_SUBJ             exists:Subject
meta      SARE_NO_SUBJ          !SARE_SUBJ

header    SARE_SUBJ             Subject =~ m'\S'
meta      SARE_BLANK_SUBJ       !SARE_SUBJ

body      SARE_BODY             m'\S'
meta      SARE_BODY_BLANK       !SARE_BODY 

meta      SARE_EMPTY_SUBJ_BODY  ( SARE_NO_SUBJ || SARE_BLANK_SUBJ ) && SARE_BODY_BLANK

OVERALL%   SPAM%     HAM%     S/O    RANK   SCORE  NAME
  95115    59678    35437    0.627   0.00    0.00  (all messages)
100.000  62.7430  37.2570    0.627   0.00    0.00  (all messages as %)
  2.295   3.3094   0.5870    0.849   0.00    1.00  SARE_BLANK_SUBJ
  0.139   0.1843   0.0621    0.748   0.00    1.00  SARE_BODY_BLANK
  2.295   3.3094   0.5870    0.849   0.00    1.00  SARE_NO_SUBJ
  0.130   0.1826   0.0423    0.812   0.00    1.00  SARE_EMPTY_SUBJ_BODY
 99.861  99.8157  99.9379    0.500   0.00    1.00  SARE_BODY
 97.705  96.6906  99.4130    0.493   0.00    1.00  SARE_SUBJ

An S/O of 0.812 for SARE_EMPTY_SUBJ_BODY is maybe worth a point or so,
but it's not a strong enough indicator of spam to be worth much.

Bob Menschel




Re: blank subject and contents

Posted by Loren Wilton <lw...@earthlink.net>.
> We're getting hit with a lot of emails with blank subject lines and blank
> contents. Could be some kind of address verification robot. Is SA supposed
> to filter these? If not, does anyone have some custom rules that would do
it?

My theory is this is the result of some newbie spammer that doesn't know how
to drive the spam tool and screwed up the configuration.

SA doesn't have a blank message rule, but SARE does.  Don't recall which
ruleset it is in, but someone (maybe Bob) posted the rule last week.

        Loren


Re: blank subject and contents

Posted by Stuart Johnston <st...@ebby.com>.
Jeff Koch wrote:
> 
> Hi:
> 
> We're getting hit with a lot of emails with blank subject lines and 
> blank contents. Could be some kind of address verification robot. Is SA 
> supposed to filter these? If not, does anyone have some custom rules 
> that would do it?

I asked about this last week, search for "blank message".

In summary, you will probably want something like:

rawbody __HAS_BODY  /\S/
meta LOCAL_EMPTY_MESSAGE  (!__HAS_BODY && SARE_TOCC_NONE)

You'll need SARE's 70_sare_header3.cf.  The main problem is that the 
body rules (even rawbody) are processed after attachments have been 
removed so you may hit some ham that only has an attachment.  The 
SARE_TOCC_NONE should help avoid the ham hits.

Stuart Johnston
Ebby Halliday, Realtors