Internet Explorer 5.01 through 6 SP1 allows remote attackers to spoof the domain of a URL via a “%01” character before an @ sign in the user@domain portion of the URL, which hides the rest of the URL, including the real site, in the address bar, aka the “Improper URL Canonicalization Vulnerability.”
www.kb.cert.org/vuls/id/652278
www.securityfocus.com/archive/1/346948
www.us-cert.gov/cas/techalerts/TA04-033A.html
www.zapthedingbat.com/security/ex01/vun1.htm
docs.microsoft.com/en-us/security-updates/securitybulletins/2004/ms04-004
exchange.xforce.ibmcloud.com/vulnerabilities/13935
oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A490
oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A491
oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A510
oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A511
oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A512
oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A513
oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A526