Question
Microsoft Outlook will remove some extraneous characters from a
file attachment resulting in the actual change of the file name.
For example, a Unix user sends the file
foobar."v"b"s"
to an Outlook user, Outlook will remove the "’s and make the file name
foobar.vbs
It seems that different builds of Outlook will treat the file differently.
In one version clicking on the paper clip icon in the preview pane displayed
the full name including " marks, another (same major version) copy displayed
the modified form.
Either way, Outlook will attempt to open the file by it’s new filename.
Can GMS Anti-Spam protect Outlook users from this exploit?
Answer
Yes.
GMS Anti-Spam will strip out these characters prior to running the banned extension checks.
It should be noted that this is only a fix for an MS Outlook bug and would not affect any other clients. GMS Webmail was already immune to this type of attack.
See Also:
Keywords:JUCE rejectattachext reject attachment extensions Spam checker GMS Anti-spam anti spam antispam