Michael Krax demonstrates that the download dialog and security dialogs can be
spoofed by partially covering them with an overlapping window. Some users may
not notice the OS window border and browser statusbar bisecting what appears to
be a single dialog, and be convinced by the spoofing text of the top-most window
to click on the "Allow" or "Open" button of the window below.
If the security dialog button is clicked signed scripts could perform any action
on the users machine.
If the download button is clicked a file could be downloaded to the default
download location. If the target file MIME type is one handled by a helper app
clicking the button could launch that helper app. If there's a known exploit in
a popular or default helper app then opening the attackers file in that app
could take advantage of that exploit.
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on the solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.