Tung wrote:
> COuld it be possible for a spammer to send an email
> with additional headers that are exactly like SA's
> with "X-Spam-FLag: NO" to trick the MDA filtering
> matches? Since SA's headers are at the end filtering
> would stop once it matches the fake headers.

That would depend on your setup;  but if you're using the most common
method to call SA (procmail), then you call SA *before* procmail decides
where to file the message based on the X-Spam* headers.

Any other calling method should act in much the same way, IMO.

In one particular case, I set procmail to file message with X-Spam* tags
of one variety in my spam folder, because they scored *very* high on a
different system under my control and so I was willing to trust that
header.

SA itself will more or less ignore any existing X-Spam* headers and
overwrite them with "new" information if a message passes through again.

All of this assumes you're using report_safe 0, instead of one of the
other tagging modes.

-kgd
-- 
"Sendmail administration is not black magic.  There are legitimate
technical reasons why it requires the sacrificing of a live chicken."
   - Unknown

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