Revision Note: Advisory Published Advisory Summary:Microsoft is investigating new public reports of a vulnerability in older versions of Microsoft Internet Explorer. Based on our investigation, this vulnerability could allow an attacker to execute arbitrary code on the user's system in the security context of the logged-on user. The attacker could do this by one or more of the following actions: By hosting a specially crafted Windows Metafile (WMF) image on a malicious Web site; By convincing a user to open a specially crafted e-mail attachment; By convincing a user to click on a link in an e-mail message that takes the user to a malicious Web site; or By sending a specially crafted e-mail message to Outlook Express users, which they view in the preview pane. Note This is not the same issue as the one addressed by Microsoft Security Bulletin MS06-001 (912919). The vulnerability exists in: Internet Explorer 5.01 Service Pack 4 on Microsoft Windows 2000 Service Pack 4 and Internet Explorer 5.5 Service Pack 2 on Microsoft Windows Millennium. Microsoft has determined that an attacker who exploits this vulnerability would have no way to force users to visit a malicious Web site. Instead, an attacker would have to persuade them to visit the Web site, typically by getting them to click a link that takes them to the attacker's Web site. It could also be possible to display specially crafted Web content by using banner advertisements or by using other methods to deliver Web content to affected systems. In an e-mail based attack, customers would have to click a link to the malicious Web site, preview a malicious e-mail message, or open an attachment that exploited the vulnerability. In both Web-based and e-mail based attacks, the code would execute in the security context of the logged-on user. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights. Microsoft will continue to investigate these reports and provide additional guid

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