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vexim / vexim2

Virtual Exim 2
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Exim 4.88 does not support demime #232

Closed ecki closed 7 years ago

ecki commented 7 years ago

Since Exim 4.88 (on FreeBSD) the "demime" ACL option is removed. I needed to remove some of the rules in vexim-acl-check-content.conf, is it planned to provide a new temlate for this?

rimas-kudelis commented 7 years ago

I guess we'll just remove the topmost 6 lines from vexim-acl-check-content.conf.

Udera commented 7 years ago

Removing is just a workaround. There is now a special acl-list for mime-variables: http://www.exim.org/exim-html-current/doc/html/spec_html/ch-content_scanning_at_acl_time.html

Rules are a bit longer and more diverse, I found a list with some examples here: http://wiki.wlug.org.nz/EximMailFilter

Thanks to regexp, we could block potentially dangerous double extensions like .doc.exe. Or only allow a few exceptions like .tar.gz. We should test these rule with some standard mail programs and webmailers.

rimas-kudelis commented 7 years ago

Ahh, github search didn't tell me that the second filter in vexim-acl-check-content.conf also uses demime, so I was under an impression that we're only using this option to filter out emails with MIME errors.

I doubt it's worthy to filter particularly on double extensions though, if we disallow .exe and similar dangerous attachments in general.