Boundary space gap
Posted on 2005-05-16
A few of our clients are unable to receive email from us due to the message getting blocked by their spam filter (mail protector). They have have had several reports from their users that emails from us are being destroyed for containing a vulnerability called "[outlook 'boundary space gap' vulnerability]". Explanation of this vulnerability: "This vulnerability occurs when there is a space or tab in the MIME boundary. This is not RFC compliant, but Outlook will treat it as valid and be able to see a virus that virus scanners will not usually see. There is no legitimate reason for an email to be formed like this."
We are running exchange 5.5 and exchange 2003. Our IMC is exchange 5.5. We have no record of any changes causing something like this. Is there anything that needs to be changed to allow our e-mails to get to this client? I have also ran virus scans on both servers and multiple clients which all prove negative. Our outgoing mail is scanned via Clearswift mimesweeper antivirus. We called clearswift and they said their product does not affect the MIME header at all. Any ideas?