S/MIME signature corrupted with attachments

Use this forum if you have installed hMailServer and want to ask a question related to a production release of hMailServer. Before posting, please read the troubleshooting guide. A large part of all reported issues are already described in detail here.
Post Reply
mikew
New user
New user
Posts: 13
Joined: 2007-05-06 11:43

S/MIME signature corrupted with attachments

Post by mikew » 2012-07-13 17:08

hMailserver 5.3.3-B1879 is corrupting S/MIME signatures, when the mail has attachments.
The problem occurs due to modified MIME headers in multi-part messages.

For example, the correct mail contains the following MIME header (note: multiple lines; "filename" indented). That's how Thunderbird creates the mail.

Code: Select all

Content-Disposition: attachment;
 filename="attachment.txt"
After reception with hMailserver it looks like this (note: a single line).

Code: Select all

Content-Disposition: attachment; filename="attachment.txt"
When I copy the original MIME headers to the received mail, the S/MIME signature matches again. The MIME body is not touched.
Attachments
smime.zip
Mail bodies.
(1.98 KiB) Downloaded 95 times

^DooM^
Site Admin
Posts: 13861
Joined: 2005-07-29 16:18
Location: UK

Re: S/MIME signature corrupted with attachments

Post by ^DooM^ » 2012-07-13 17:45

Anything else in the way such as AV / ASSP / SA / DPI firewall etc?
If at first you don't succeed, bomb disposal probably isn't for you! ヅ

mikew
New user
New user
Posts: 13
Joined: 2007-05-06 11:43

Re: S/MIME signature corrupted with attachments

Post by mikew » 2012-07-13 18:26

Anything else in the way such as AV / ASSP / SA / DPI firewall etc?
Nope.
The test mails have been sent directly to hMail's local SMTP. The issue also occurs when hMail is collecting from extern POP3.
ClamAV is called as a command line scanner in hMailserver when receiving the Mail. This was the only virus scanner in the whole send-receive-chain and should have no way to modify the message content.

The client (Thunderbird) fetches via IMAP. With other (external) servers this issue does not occur.

^DooM^
Site Admin
Posts: 13861
Joined: 2005-07-29 16:18
Location: UK

Re: S/MIME signature corrupted with attachments

Post by ^DooM^ » 2012-07-14 09:57

Ok check to see if the issue is not listed here http://www.hmailserver.com/devnet/?page=issuetracker if it's not please add it with steps on exactly how to recreate the issue.

Cheers!
If at first you don't succeed, bomb disposal probably isn't for you! ヅ

mikew
New user
New user
Posts: 13
Joined: 2007-05-06 11:43

Re: S/MIME signature corrupted with attachments

Post by mikew » 2012-07-14 12:08

I created issue 385.
Thanks for the help so far!

Post Reply