Re: [Extra] Ben Campbell's Discuss on draft-ietf-extra-sieve-fcc-08: (with DISCUSS and COMMENT)

Ben Campbell <ben@nostrum.com> Thu, 10 January 2019 14:56 UTC

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From: Ben Campbell <ben@nostrum.com>
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Date: Thu, 10 Jan 2019 08:56:16 -0600
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Cc: extra@ietf.org, yaojk@cnnic.cn, draft-ietf-extra-sieve-fcc@ietf.org, The IESG <iesg@ietf.org>, extra-chairs@ietf.org
To: Alexey Melnikov <aamelnikov@fastmail.fm>
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Subject: Re: [Extra] Ben Campbell's Discuss on draft-ietf-extra-sieve-fcc-08: (with DISCUSS and COMMENT)
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> On Jan 10, 2019, at 2:42 AM, Alexey Melnikov <aamelnikov@fastmail.fm>; wrote:
> 
> Hi Ben,
> 
>> On 9 Jan 2019, at 21:51, Ben Campbell <ben@nostrum.com>; wrote:
>> 
>> ----------------------------------------------------------------------
>> DISCUSS:
>> ----------------------------------------------------------------------
>> 
>> Thanks for the work on this. I plan to ballot "yes", but have one item I think
>> needs to be discussed first:
>> 
>> The security considerations say that this extension adds no new considerations
>> not already present in [RFC5228], [RFC5230], [RFC5435], and [RFC6131]. I'm not
>> sure that that is true.
>> 
>> It seems like the ability to insert a copy of message into a mailbox might have
>> security and/or privacy considerations.
> 
> Can you give me an idea of what you have in mind here, other than putting the user (Sieve script owner) over quota?

I can’t say that I know what the security considerations might be; I’m just skeptical that the answer is “no new considerations." The authors of 5228 thought “fileinto” could be dangerous. Do we know why?

> 
> In particular, what are the possible privacy implications?

Could there be issues with, say, shared mailboxes? Or storing cleartext for mail that would be sent encrypted?

I suspect the answers may be more IMAP related than sieve related, but even that might suggest citing something IMAP related.

Ben.

> 
> Thank you,
> Alexey
>> This seems analogous to the "fileinto"
>> action. I looked for security considerations for that in RFC 5228. All I found
>> was a statement that "fileinfo" can be dangerous, but no elaboration on the
>> nature of the danger or how it might be mitigated. So while I agree that fcc
>> would have similar considerations as "fileinfo", I'm not sure those
>> considerations have been adequately documented.  (I expect people will point me
>> to something I missed, or where some other analogous feature is documented, in
>> which case I will clear.)
>