Re: What does "UNCHECKED" really mean?

Damian <[email protected]> Tue, 17 Jun 2025 10:02:45 +0200
Newsgroups	gmane.mail.virus.amavis.user
Message-ID	<[email protected]>
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> What I've found is that the problem is triggered by having a 
> multi-part message, where one or more parts contains multiple 
> Content-Transfer-Encoding headers... 

This behaviour comes from [1,2,3]:

> Messages with ambiguous content should be treated as a security risk. 
> In particular, if MIME::Parser is used in an email security tool, 
> ambiguous messages should not be delivered to end-users.

Per default, Amavis delivers them, but flags them as "CC_UNCHECKED,3", 
which is a dedicated subcategory for this case.

[1] https://gitlab.com/amavis/amavis/-/issues/112
[2] https://metacpan.org/pod/MIME::Entity#ambiguous_content
[3] https://metacpan.org/pod/MIME::Parser#ambiguous_content

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    <blockquote type="cite"
      cite="mid:[email protected]">What
      I've found is that the problem is triggered by having a multi-part
      message, where one or more parts contains multiple
      Content-Transfer-Encoding headers...
    </blockquote>
    <p>This behaviour comes from [1,2,3]:<br>
    </p>
    <p>
      <blockquote type="cite">Messages with ambiguous content should be
        treated as a security risk. In particular, if MIME::Parser is
        used in an email security tool, ambiguous messages should not be
        delivered to end-users.</blockquote>
    </p>
    <p>Per default, Amavis delivers them, but flags them as
      "CC_UNCHECKED,3", which is a dedicated subcategory for this case.<br>
    </p>
    <p>[1] <a class="moz-txt-link-freetext" href="https://gitlab.com/amavis/amavis/-/issues/112">https://gitlab.com/amavis/amavis/-/issues/112</a><br>
      [2] <a class="moz-txt-link-freetext" href="https://metacpan.org/pod/MIME::Entity#ambiguous_content">https://metacpan.org/pod/MIME::Entity#ambiguous_content</a><br>
      [3] <a class="moz-txt-link-freetext" href="https://metacpan.org/pod/MIME::Parser#ambiguous_content">https://metacpan.org/pod/MIME::Parser#ambiguous_content</a><br>
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