Firefox before 1.0.1 and Mozilla before 1.7.6 allows remote attackers to spoof the SSL "secure site" lock icon via (1) a web site that does not finish loading, which shows the lock of the previous site, (2) a non-HTTP server that uses SSL, which causes the lock to be displayed when the SSL handshake is completed, or (3) a URL that generates an HTTP 204 error, which updates the icon and location information but does not change the display of the original site.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A9533
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A100044
https://bugzilla.mozilla.org/show_bug.cgi?id=277564
https://bugzilla.mozilla.org/show_bug.cgi?id=276720
https://bugzilla.mozilla.org/show_bug.cgi?id=268483
https://bugzilla.mozilla.org/show_bug.cgi?id=258048
http://www.securityfocus.com/bid/12659
http://www.redhat.com/support/errata/RHSA-2005-384.html
http://www.redhat.com/support/errata/RHSA-2005-176.html
http://www.mozilla.org/security/announce/mfsa2005-14.html