email forwarding breaks the digital signature

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Conzi
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email forwarding breaks the digital signature

Post by Conzi » 2020-01-11 23:12

Hi!

I have a problem with emails forwarding and digital signature.
Scenario:
two accounts on same hmailserver.
test1@test.loc
test2@test.loc

mail is downloaded to the test1@test.loc account via pop3 (external account) and I set up a forwarding to test2@test.loc, so I should find two identical emails...
Image
Image

but on the SAME email ont test1@test.loc account the email digital signature is valid and on the same email on test2@test.loc account the email digital signature is NOT valid.
digital signature on test1@test.loc email:
Image

digital signature ont test2@test.loc email:
Image


Is this a bug?

note: hmailserver 5.6.8-b2494 - 5.6.8-b2431 (with mariadb or mssql ce, same result) (tested also 5.7.0-b2497 with no luck)
same behaviour with forward made by account rule
on Outlook same behaviour
no antivirus, no script, nothing at all (is a simple testing installation)
This hmailserver is installed on lawyer office.. so it's really a problem

Any help is very appreciated

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jimimaseye
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Re: email forwarding breaks the digital signature

Post by jimimaseye » 2020-01-11 23:23

No its not a bug. (Why do people always assume that by defaults when 90% is understanding and human error).

Forwarding is a new email being created. New recipient. New time. Completely different email albeit looking identical. Therefore the contents have changed since signing

[Entered by mobile. Excuse my spelling.]
5.7 on test.
SpamassassinForWindows 3.4.0 spamd service
AV: Clamwin + Clamd service + sanesecurity defs : https://www.hmailserver.com/forum/viewtopic.php?f=21&t=26829

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Conzi
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Re: email forwarding breaks the digital signature

Post by Conzi » 2020-01-11 23:34

mmhh..
how can I copy/forward emails to other accounts without breaking the digital signature?

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jimimaseye
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Re: email forwarding breaks the digital signature

Post by jimimaseye » 2020-01-11 23:45

Try doing it at scripting level on the onexternaldownload section to create a copy .

[Entered by mobile. Excuse my spelling.]
5.7 on test.
SpamassassinForWindows 3.4.0 spamd service
AV: Clamwin + Clamd service + sanesecurity defs : https://www.hmailserver.com/forum/viewtopic.php?f=21&t=26829

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mattg
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Re: email forwarding breaks the digital signature

Post by mattg » 2020-01-12 00:21

Conzi wrote:
2020-01-11 23:34
how can I copy/forward emails to other accounts without breaking the digital signature?
Hi Conzi,

isn't that the point of the digitial signature, that the message can't be altered without breaking the signature

This isn't about DKIM, this is Message level signature through PGP or similar, correct?
Just 'cause I link to a page and say little else doesn't mean I am not being nice.
https://www.hmailserver.com/documentation

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Conzi
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Re: email forwarding breaks the digital signature

Post by Conzi » 2020-01-12 00:48

No, This isn't about DKIM. and the message isn't encrypted, only digitally signed.
I will try to copy the messages via imap to public folders (with right for every user, only local user of domain in hmailserver)

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Conzi
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Re: email forwarding breaks the digital signature

Post by Conzi » 2020-01-12 00:49

jimimaseye wrote:
2020-01-11 23:45
Try doing it at scripting level on the onexternaldownload section to create a copy .

[Entered by mobile. Excuse my spelling.]
Unfortunately i don't have skill for scripting... but thanks for the hint.

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mattg
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Re: email forwarding breaks the digital signature

Post by mattg » 2020-01-12 07:44

Conzi wrote:
2020-01-12 00:48
No, This isn't about DKIM. and the message isn't encrypted, only digitally signed.
But if it is digitally signed, isn't that signed to the recipient
Just 'cause I link to a page and say little else doesn't mean I am not being nice.
https://www.hmailserver.com/documentation

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