Severity: Low

It seems that (in Untangle 5.0.x anyway) the Quarantine email that users receive links back to the untangle.com site.... the properties of the 'attachment' icon (paperclip) indicate that the image source is:
http://www.untangle.com/mail_blast/quarantine/images/with_attach.png

rather than any of the 'better' options of:
  1. embedded in the email itself, or;
  2. linking back to the site's own untangle proxy.


For clarity: I don't in any way see this as malicious, but it means that users will receive a sub-optimal quarantine email in secure environments. [It also raises the workload for Untangle.com's webserver and may skew your webstatistics! ]

Specifically:
Later releases of MS Outlook will block it.
Some webmail clients will replace it was a big, scary 'Unsafe images not displayed for security reasons' warning...