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The following is an archive of a post made to our 'vox-tech mailing list' by one of its subscribers.

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Re: [vox-tech] Virus deluge
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Re: [vox-tech] Virus deluge



on Tue, Jan 27, 2004 at 10:39:17PM -0800, Mark K. Kim (markslist@cbreak.org) wrote:
> On Tue, 27 Jan 2004, Karsten M. Self wrote:
> 
> > > ================================================================================
> > > :0 B
> > > * -1
> > > * 1^0 ^Content-Transfer-Encoding: base64
> > > * 1^0 1rrAeM0gDQdlmmtNtWVfG3QRFA672grQLlgIdDhobVVL2XMWVlc87bWFzho6IHtwAj2d9r
> > > * 1^0 Ga9SG/3//7dSpCoQS7DvKZAv72JQKWmvdKWWbadVD/D//9vSfeg2mRbgbKcMvEZXguXrNq
> > > * 1^0 TBuvVXOm//9/idxR1/7/Y6uPvh3LTd755dO39hzsPp/6sfv///8xZXpCOlu2J40AUMvgDP
> > > * 1^0 Q2VDAuk6pQf8sthCvHkbFDMACWK8hd0C2mSZPSKSIjutcMMWTmfwLUdsuyF4o1Tjemh5hk
> > > * 1^0 Z3h2Z0tDwwdp3y78fy10dmV5LTIuMG9xcIxfY05wdXJmmaHdCjNcdmkLRDvZ1r5tSGRWLV
> > > * 1^0 V0jTDPIH0MgIsEjTDDKYiAqARYEDNnhPUmWtFnAb4JuraGYHK2nGAwbeAiBFcj2UWskGOE
> > > {
> > >     LOG="LOG: Virus: (Mydoom / Novar)"
> > >
> > >     :0:
> > >     Virus/
> > > }
> > > ================================================================================
> 
> I'm new to procmail so can I ask some questions?
> 
> What do ":0 B", "-1", and "1^0" do?  Does LOG do anything?

Peter got most of this.

:<number> starts a recipie.  Used to be that <number> was (IIRC) the
number of lines in the recipie.  Now it's typically set to 0, and has no
special significance.

'B' scans body

: *after* '0' indicates a lockfile.  Any rule that writes to a file
    _should_ use a lockfile.  Rules which invoke a program '| command'
    or delivery '! address' _don't_ need a lockfile.

For more information:  man procmail; man procmailrc; man procmailex



* <number>
* <number>^<number>

...are scoring rules.  The first number says what to add.  The
second says when to add it, and by how much.  I understand this only
vaguely.  

Essentially:

  - No trailing value means "apply this score once in the evaluation of
    this recipie".

  - A trailing '0' means "apply this score once and only once if it is
    matched"

  - A trialing '1' means "add the score for *each* occurance of a match.

  - 0 <x<1 : Each successive match contributes less than the prior one.
             The score asymptotically approaches a value.

  - 1 < x  : Each successive match contributes more than the prior one.
             The score grows asymptotically.

For more information:  man procmailsc



The rule says, in English:

  - Start a recipie. Scan the body.
  - Use scoring.  Set a default score of '-1' (require two matches for
    the rule to take effect)
  - Add one for a base64 MIME encoding demarcation.
  - Add one for any of the following legacy MS Windows executable
    signatures.
  - The condition in braces is met if two rules matched.
  - (If logging) log that this was a MyDoom virus match.
  - Write to the Virus folder, a Maildir directory (the trailing '/'
    indicates).


> Thanks!  The rules seem to be working so far...

NP.


Peace.

-- 
Karsten M. Self <kmself@ix.netcom.com>        http://kmself.home.netcom.com/
 What Part of "Gestalt" don't you understand?
   Sick of mal-formed websites?  A stylesheet to override poor design:
     http://twiki.iwethey.org/Main/UserContentCSS

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