882002 - apparent plain text mail forwarded as attachment bounces as having "potentially executable attachment"

Status: NEW

(SeaMonkey :: MailNews: General, defect)

Description

[Felix Miata]

Attachment: actual email message extracted manually from mail "folder" file

To reproduce:
1-View -> Message Body As -> Plain Text
2-Set forward messages as attachment in preferences
3-Select a Content-Type: multipart/mixed message that is not identified as "HTML" in normal header view
4-Forward the message to a valid email address

Actual behavior:
1-message bounces with message:
"    This message has been rejected because it has
    a potentially executable attachment "Re: Anaconda grub install options?.eml"
    This form of attachment has been used by
    recent viruses or other malware.
    If you meant to send this file then please
    package it up as a zip file and resend it."
2-NAICT, it is recipient anti-spam software that causes the bounce due to misidentification of attachment as an executable file

Expected behavior:
1-message is not misidentified as executable
2-message does not bounce

Note that the recommendation to package up as a zip file cannot work correctly, as SeaMonkey will not save the message to file without either multiplying its size with its own formatting, or deleting headers:

Comment 1

[Felix Miata]

Attachment: result of saving same message to disk as file

Mozilla/5.0 (X11; Linux i686; rv:20.0) Gecko/20100101 SeaMonkey/2.17.1; Build ID: 20130410210803

Comment 2

[Felix Miata]

Attachment: message forwarded saved as file to disk from view source window

Comment 3

[Felix Miata]

Attachment: bounced message saved as file to disk from mail view window

Comment 4

[Felix Miata]

Attachment: bounced message saved as file to disk from view source window

Comment 5

[rsx11m]

That's usually caused by the ".eml" suffix in the attachment name, which many servers use as a trivial check whether or not to allow an attachment.

> Content-Type: message/rfc822;
>  name="Re: Anaconda grub install options?.eml"

You can remove the ".eml" for all messages you compose by resetting the mail.forward_add_extension preference to false.

 1. Type about:config into the browser's location bar
 2. Confirm the warning
 3. Copy-paste or type mail.forward_add_extension into the search bar
 4. Double-click on the entry that remains to toggle it to false

Now it should work.