Microsoft has confirmed this vulnerability in a security bulletin and released software updates that correct it.
Systems running the following versions of Microsoft Windows are affected:
Windows 2000 SP4 and prior††
Windows XP SP3 and prior
Windows XP Professional x64 Edition SP2 and prior
Windows Server 2003 SP2 and prior
Windows Server 2003 x64 Edition SP2 and prior
Windows Server 2003 for Itanium-based Systems SP2 and prior
Windows Vista SP2 and prior
Windows Vista x64 Edition SP2 and prior
Windows Server 2008 for 32-bit Systems SP2 and prior
Windows Server 2008 for x64-based Systems SP2 and prior
Windows Server 2008 for Itanium-based Systems SP2 and prior
Attackers cannot directly exploit this vulnerability and instead must rely on user participation to accomplish an exploit.† An attacker must convince a user to view a malicious website, likely by providing links to the user in e-mail messages.† Attackers may also include malicious content on public or compromised websites to accomplish an exploit, but an attacker could not force the user to view the malicious content.† Attackers may use social engineering techniques to convince users to view malicious websites, possibly by convincing the user that the source of a URL or website is trusted.
Windows Server 2003 and Windows Server 2008 systems are less at risk because Internet Explorer runs in the Enhanced Security Configuration mode on these systems.† Additionally, users on Windows Server systems may be less likely to browse to untrusted, external websites.
End-user systems, such as those running Windows 2000, Windows XP, or Windows Vista, may be at greater risk because users may regularly visit unknown websites and run applications with elevated privileges.† An exploit that runs when the user holds elevated or Administrator privileges could allow the attacker to execute arbitrary code, resulting in a complete system compromise.
Microsoft has released a security bulletin at the following link: MS09-045
An unauthenticated, remote attacker could exploit this vulnerability to execute arbitrary code with the privileges of the targeted user.† If that user holds elevated privileges, the attacker could completely compromise the vulnerable system.
Administrators are advised to apply the available software updates.
Administrators may consider configuring Internet Explorer to prompt users before running Active Scripting or ActiveX controls by setting the Internet and Local Intranet security zone settings to High. Alternately, administrators could disable Active Scripting and ActiveX controls in these security zones.
Users are advised not to open e-mail messages from suspicious or unrecognized sources. If users cannot verify that links or attachments included in e-mail messages are safe, they are advised not to open them.
Users are advised to run applications with the least necessary privileges.
Administrators may consider using the Microsoft Baseline Security Analyzer (MBSA) scan tool to identify common security misconfigurations and missing security updates on system endpoints.
Microsoft customers can obtain updates directly by using the links in the security bulletin. These updates are also distributed by Windows automatic update features and available on the Windows Update website. Microsoft Windows Server Update Services (WSUS), Systems Management Server, and System Center Configuration Manager can assist administrators in deploying software updates.
Home Edition Base, SP1, SP2, SP3 | Professional Edition Base, SP1, SP2, SP3 | Professional x64 (AMD/EM64T) Base, SP2
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