Re: [mailop] “Moderation pending” messages

2017-11-23 Thread Grant Taylor via mailop 

On 11/22/2017 06:47 PM, Brandon Long via mailop wrote:
I never liked the design choice which said permission failure had to 
look like nonexistence,


Is this a reference to the mentality of needing to say "username or 
password" instead of "password" in an attempt to not confirm that a 
"username" is accurate, just applied to Google Group names?




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Re: [mailop] “Moderation pending” messages

2017-11-22 Thread Leo Gaspard 
Hmm, I was mostly thinking “oh, you already have technical measures
against backscatter” (like sending the bounce only when SPF/DKIM are
defined and match), and deducing from there that maybe the same
protection granted to a “moderation pending” email would work?

Basically, I'm thinking “moderation pending” is overall the same as
“permission denied,” but then maybe spam moderation would be a source of
too much backscatter? I haven't made stats on how many spams come with
existing and matching spf/dkim policies but spoofed bounce address, but
I wouldn't think it is high, thanks to spf/dkim being designed to
prevent spoofing? (and “backscatter” to a spammer-owned email address
doesn't sound like a big deal to me)


On 11/23/2017 02:47 AM, Brandon Long wrote:
> So, you're answer to whether we should make more backscatter is that we
> already make some so what's the big deal?
> 
> Hmm
> 
> This seems like the most obvious case of backscatter, when we think
> something is spam.
> 
> I never liked the design choice which said permission failure had to
> look like nonexistence, especially when permission can only be decided
> based on the full message, so it can't be done at rcpt to time.
> 
> Brandon
> 
> On Wed, Nov 22, 2017, 4:21 PM Leo Gaspard  wrote:
> 
> On 11/22/2017 04:51 PM, Brandon Long wrote:
> > If you send me the full headers I can take a look, but yes, sounds
> like
> > either moderation or spam moderation.
> 
> So after checking, it was indeed spam moderation. Thanks Brandon!
> 
> I'd just like to raise the issue of whether to send a “your message is
> pending moderation” answering messages that are enqueued to the
> moderator's queue.
> 
> To me, the main advantage is not letting people think their messages are
> dropped (I plead guilty to this one), and the main drawback is the risk
> of backscatter.
> 
> However, for backscatter, currently google groups do send a bounce when
> an email is sent to a moderation-only group from a non-in-group email
> address:
> 
> --8<--8<--
> From: Mail Delivery Subsystem  >
> Subject: Delivery Status Notification (Failure)
> 
> Hello [source email address],
> 
> We're writing to let you know that the group you tried to contact
> ([group name]) may not exist, or you may not have permission to post
> messages to the group. A few more details on why you weren't able to
> post:
> 
>  * You might have spelled or formatted the group name incorrectly.
>  * The owner of the group may have removed this group.
>  * You may need to join the group before receiving permission to post.
>  * This group may not be open to posting.
> 
> If you have questions related to this or any other Google Group, visit
> the Help Center at https://groups.google.com/support/.
> 
> Thanks,
> 
> Google Groups
> 
> 
> 
> - Original message -
> 
> [full copy with headers of the original message]
> -->8-->8--
> 
> So, currently google groups are already a source of potential
> backscatter, as far as I understand.
> 
> I guess there are countermeasures in place to avoid doing this for any
> incoming mail, and so believe with the same countermeasures a “message
> pending moderation” email could be sent without additional damage?
> 
> Just in case there are no countermeasures (and maybe this would deserve
> another thread, if it is controversial?), a simple countermeasure could,
> I guess, be to check the incoming message passes SPF and only send a
> bounce in this case: if SPF passes then the MAIL FROM email is
> legitimate, and thus the bounce would be sent to the right address. (If
> the bounce is sent to the From: address checking DKIM passed would sound
> equally right to me).
> This would amount to a header check, as by the time the email is put in
> the moderation queue its headers already include the spf=pass dkim=pass
> dmarc=pass from ARC-Authentication-Results (if I can guess how the
> moderation queue is handled based on message timings from the headers).
> 
> What do you all think about this?
> 
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Re: [mailop] “Moderation pending” messages (was: Re: Google groups dropping mail?)

2017-11-22 Thread Brandon Long via mailop 
So, you're answer to whether we should make more backscatter is that we
already make some so what's the big deal?

Hmm

This seems like the most obvious case of backscatter, when we think
something is spam.

I never liked the design choice which said permission failure had to look
like nonexistence, especially when permission can only be decided based on
the full message, so it can't be done at rcpt to time.

Brandon

On Wed, Nov 22, 2017, 4:21 PM Leo Gaspard  wrote:

> On 11/22/2017 04:51 PM, Brandon Long wrote:
> > If you send me the full headers I can take a look, but yes, sounds like
> > either moderation or spam moderation.
>
> So after checking, it was indeed spam moderation. Thanks Brandon!
>
> I'd just like to raise the issue of whether to send a “your message is
> pending moderation” answering messages that are enqueued to the
> moderator's queue.
>
> To me, the main advantage is not letting people think their messages are
> dropped (I plead guilty to this one), and the main drawback is the risk
> of backscatter.
>
> However, for backscatter, currently google groups do send a bounce when
> an email is sent to a moderation-only group from a non-in-group email
> address:
>
> --8<--8<--
> From: Mail Delivery Subsystem 
> Subject: Delivery Status Notification (Failure)
>
> Hello [source email address],
>
> We're writing to let you know that the group you tried to contact
> ([group name]) may not exist, or you may not have permission to post
> messages to the group. A few more details on why you weren't able to post:
>
>  * You might have spelled or formatted the group name incorrectly.
>  * The owner of the group may have removed this group.
>  * You may need to join the group before receiving permission to post.
>  * This group may not be open to posting.
>
> If you have questions related to this or any other Google Group, visit
> the Help Center at https://groups.google.com/support/.
>
> Thanks,
>
> Google Groups
>
>
>
> - Original message -
>
> [full copy with headers of the original message]
> -->8-->8--
>
> So, currently google groups are already a source of potential
> backscatter, as far as I understand.
>
> I guess there are countermeasures in place to avoid doing this for any
> incoming mail, and so believe with the same countermeasures a “message
> pending moderation” email could be sent without additional damage?
>
> Just in case there are no countermeasures (and maybe this would deserve
> another thread, if it is controversial?), a simple countermeasure could,
> I guess, be to check the incoming message passes SPF and only send a
> bounce in this case: if SPF passes then the MAIL FROM email is
> legitimate, and thus the bounce would be sent to the right address. (If
> the bounce is sent to the From: address checking DKIM passed would sound
> equally right to me).
> This would amount to a header check, as by the time the email is put in
> the moderation queue its headers already include the spf=pass dkim=pass
> dmarc=pass from ARC-Authentication-Results (if I can guess how the
> moderation queue is handled based on message timings from the headers).
>
> What do you all think about this?
>
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>
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[mailop] “Moderation pending” messages (was: Re: Google groups dropping mail?)

2017-11-22 Thread Leo Gaspard 
On 11/22/2017 04:51 PM, Brandon Long wrote:
> If you send me the full headers I can take a look, but yes, sounds like
> either moderation or spam moderation.

So after checking, it was indeed spam moderation. Thanks Brandon!

I'd just like to raise the issue of whether to send a “your message is
pending moderation” answering messages that are enqueued to the
moderator's queue.

To me, the main advantage is not letting people think their messages are
dropped (I plead guilty to this one), and the main drawback is the risk
of backscatter.

However, for backscatter, currently google groups do send a bounce when
an email is sent to a moderation-only group from a non-in-group email
address:

--8<--8<--
From: Mail Delivery Subsystem 
Subject: Delivery Status Notification (Failure)

Hello [source email address],

We're writing to let you know that the group you tried to contact
([group name]) may not exist, or you may not have permission to post
messages to the group. A few more details on why you weren't able to post:

 * You might have spelled or formatted the group name incorrectly.
 * The owner of the group may have removed this group.
 * You may need to join the group before receiving permission to post.
 * This group may not be open to posting.

If you have questions related to this or any other Google Group, visit
the Help Center at https://groups.google.com/support/.

Thanks,

Google Groups



- Original message -

[full copy with headers of the original message]
-->8-->8--

So, currently google groups are already a source of potential
backscatter, as far as I understand.

I guess there are countermeasures in place to avoid doing this for any
incoming mail, and so believe with the same countermeasures a “message
pending moderation” email could be sent without additional damage?

Just in case there are no countermeasures (and maybe this would deserve
another thread, if it is controversial?), a simple countermeasure could,
I guess, be to check the incoming message passes SPF and only send a
bounce in this case: if SPF passes then the MAIL FROM email is
legitimate, and thus the bounce would be sent to the right address. (If
the bounce is sent to the From: address checking DKIM passed would sound
equally right to me).
This would amount to a header check, as by the time the email is put in
the moderation queue its headers already include the spf=pass dkim=pass
dmarc=pass from ARC-Authentication-Results (if I can guess how the
moderation queue is handled based on message timings from the headers).

What do you all think about this?

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