On Thu, 28 Jul 2005, Phil Chambers wrote:
>
> Have you done any tests to see if rejecting spaces between : and < will block
> many non-spam mail software and have you any idea when your patch may be
> available?
The :< check is probably suitable for use on an MX, but not on a
submission server because legitimate MUA software is very bad at following
the specifications correctly.
> In the meantime, what do you think about my suggested test of camparing
> $local_part with ${rfc2047:$local_part} and rejecting if they do not match?
> I have been reluctant to use it in case I have overlooked a reason why it will
> not work.
I've just checked the details of what it would do, and it isn't what you
want: rfc2047 encodes = _ . ? which are legitimate characters to have
un-escaped in a local part. It would probably be better to use a regex
check for [[:cntrl:][:^ascii:]] (i.e. characters 0-31 and 128-255).
Philip is of course correct about the limited value of checks like these,
but malware hangs around on the Internet for an awfully long time so I
think it's still worth defending against the old junk.
Tony.
--
<fanf@???> <dot@???>
http://dotat.at/ ${sg{\N${sg{\
N\}{([^N]*)(.)(.)(.*)}{\$1\$3\$2\$1\$3\n\$2\$3\$4\$3\n\$3\$2\$4}}\
\N}{([^N]*)(.)(.)(.*)}{\$1\$3\$2\$1\$3\n\$2\$3\$4\$3\n\$3\$2\$4}}
