[Mailman-Users] UTF-8 From and Reply-to addresses not getting properly processed.

[Lindsay Haisley]

On Sun, 2020-02-16 at 14:09 -0500, Richard Damon wrote:
> One thing to note is that you seem to have two different filters at work 
> here, one being non-member post, which you want to Discard, and messages 
> with 'bad' words in the subject, which you define to Hold. A message 
> which matches both filters will be acted by the first filter that the 
> message hits.

The only relevant spam filter in effect here is:

(?i)Subject: .*[f---]
[dashes substituted to avoid downline filters on this list]

The disposition (Action) specified for this filter is Discard, not
Hold. I don't believe we have a "bad words" filter as such, nor a
relevant criterion which is set to "Hold" which might override existing
settings. Some of these problem posts don't have "f---" in the Subject
header, (e.g. "I Instacheat") but contain "f---" in the body. Filtering
on the body content for prohibited words, if it's supported (and I
don't think it is), should not trump generic_nonmember_action, which is
why I suspect the problem posts may be from moderated members, but the
list has 859 members, most of whom are legit but unknown to the list
admin.

The primary problem here is what I identified as ascii-armored UTF-8
encoding (Mark says they're wrapped in base64 encoding) so we don't
have any idea what the _real_ From address is, so we can't search the
subscriber list, nor set up specific rules by sender address.

The Administrative Requests list decodes the Subject header, which is
similarly encoded, but not the From address. Without this, we're
shooting in the dark. As I said, if the spamming senders address is
actually a moderated subscriber we have no way of knowing from the
information provided by MM 2.

Since the code is in MM2 to decode base64 headers, which it does for
the similarly encoded Subject, I should probably hack the MM code to
make it do the same for the From header before showing it in the list
of Administrative Requests (or someone else could do this, probably
faster than I could).

-- 
Lindsay Haisley       |  "The arc of history is long, but
FMP Computer Services |     it bends toward Justice"
512-259-1190          |
http://www.fmp.com    |        - Barack Obama