Microsoft Windows contains a vulnerability that could allow an unauthenticated, remote attacker to execute arbitrary code with the privileges of the user. Updates are available.
Microsoft Windows 2000 SP4 and prior, Windows XP SP3 and prior, and Windows Server 2003 SP2 and prior contain a vulnerability that could allow an unauthenticated, remote attacker to execute arbitrary code.
This vulnerability is due to errors that occur when the vulnerable application processes malformed data by the DHTML Editing Component ActiveX control. An unauthenticated, remote attacker could exploit this vulnerability by convincing a user to view a malicious website. A successful exploit could allow the attacker to execute arbitrary code with the privileges of the user.
Microsoft has confirmed this vulnerability in a security bulletin and released updated software.
Systems running the following versions of Microsoft Windows are vulnerable:
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 with SP2 and prior
To exploit this vulnerability, an attacker must convince a user to visit a malicious website. Attackers cannot directly exploit the vulnerability without user interaction and may use social engineering tactics to convince users to participate in an exploit.
If an exploit is successful, the attacker could execute arbitrary code with the privileges of the user. Systems that grant users elevated privileges are at greatest risk. If the user holds privileges equivalent to the Administrator account, the attacker could execute arbitrary code that results in a complete system compromise.
The update available from Microsoft corrects this vulnerability by removing affected code segments from the ActiveX control.
Microsoft has released a security bulletin at the following link: MS09-046
An unauthenticated, remote attacker could exploit this vulnerability to execute arbitrary code with the privileges of the user. If that user holds Administrator privileges, the attacker could execute code that results in a complete system compromise.
This vulnerability is due to errors that occur when the vulnerable application processes malformed data by the DHTML Editing Component ActiveX control. An unauthenticated, remote attacker could exploit this vulnerability by convincing a user to view a malicious website that is designed to pass malicious data to the vulnerable control. When processed, the malicious input could cause the ActiveX control to corrupt system memory. The attacker could leverage the memory corruption to execute arbitrary code with the privileges of the user.
Administrators are advised to apply the appropriate update.
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 privileges necessary.
Administrators may consider disabling the DHTML Editing Component ActiveX control by setting the killbit on the following CLSID:
Administrators are advised to implement an intrusion prevention system (IPS) or intrusion detection system (IDS) to help detect and prevent attacks that attempt to exploit this vulnerability.
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.
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