As noted in Mike Reavey's posts on The Microsoft blog and The Microsoft Security Response Center (MSRC) blog today, we have just released Security Advisory 979352. Here's the detail from Mike Reavey's post…
Based upon our investigations, we have determined that Internet Explorer was one of the vectors used in targeted and sophisticated attacks against Google and possibly other corporate networks. Today, Microsoft issued guidance to help customers mitigate a Remote Code Execution (RCE) vulnerability in Internet Explorer. Additionally, we are cooperating with Google and other companies, as well as authorities and other industry partners.
Microsoft remains committed to taking the appropriate action to help protect our customers. We released Security Advisory 979352 to provide customers with actionable guidance and tools to help with protections against exploit of this vulnerability. Microsoft has not seen widespread customer impact, rather only targeted and limited attacks exploiting IE 6 at this time. Our teams are currently working to develop an update and we will take appropriate action to protect customers when the update has met the quality bar for broad distribution. That may include releasing the update out of band.
It is important to note that complex attacks targeting specific corporate networks are becoming more prevalent in the threat landscape, therefore organizations should follow defense-in-depth best practices, and deploy multiple layers of protection to improve their security posture. In addition, Protected Mode in IE 7 on Windows Vista and later significantly reduces the ability of an attacker to impact data on a user’s machine. Customers should also enable Data Execution Prevention (DEP) which helps mitigate online attacks. DEP is enabled by default in IE 8 but must be manually enabled in prior versions.
Customers can also set Internet and Local intranet security zone settings to "High" to prompt before running ActiveX Controls and Active Scripting in these zones or configure Internet Explorer to prompt before running Active Scripting or to disable Active Scripting in the Internet and Local intranet security zone. You can find details on implementing these settings in the advisory.
Anyone believed to have been affected can visit: http://www.microsoft.com/protect/support/default.mspx and should contact the national law enforcement agency in their country. Those in the United States can contact Customer Service and Support at no charge using the PC Safety hotline at 1-866-727-2338 (PCSAFETY). Additionally, customers in the United States should contact their local FBI office or report their situation at: www.ic3.gov. Customers should follow the guidance in the advisory and our Protect Your PC guidance of enabling a firewall, getting software updates, and installing antivirus software (learn more by visiting the Protect Your PC web site). International customers can find their Regional Customer Service Representative http://support.microsoft.com/common/international.aspx.
We are also working with our Microsoft Active Protections Program (MAPP), the Microsoft Security Response Alliance (MSRA), authorities and other industry partners to help provide broader protections for customers. Together with our partners, we will continue to monitor the threat landscape and will take action against any web sites that seek to exploit this vulnerability.
The Security Advisory will be updated with any new developments so if you are not already subscribed to our comprehensive alerts, please do so in order to be alerted by email when new information is added.
This from our Security Advisories page on TechNet…
Microsoft Security Advisory (979352) – Vulnerability in Internet Explorer Could Allow Remote Code Execution, Published: January 14, 2010
Microsoft is investigating a report of a publicly exploited vulnerability in Internet Explorer. This advisory contains information about which versions of Internet Explorer are vulnerable as well as workarounds and mitigations for this issue.
Our investigation so far has shown that Internet Explorer 5.01 Service Pack 4 on Microsoft Windows 2000 Service Pack 4 is not affected, and that Internet Explorer 6 Service Pack 1 on Microsoft Windows 2000 Service Pack 4, and Internet Explorer 6, Internet Explorer 7 and Internet Explorer 8 on supported editions of Windows XP, Windows Server 2003, Windows Vista, Windows Server 2008, Windows 7, and Windows Server 2008 R2 are affected.
The vulnerability exists as an invalid pointer reference within Internet Explorer. It is possible under certain conditions for the invalid pointer to be accessed after an object is deleted. In a specially-crafted attack, in attempting to access a freed object, Internet Explorer can be caused to allow remote code execution.
At this time, we are aware of limited, active attacks attempting to use this vulnerability against Internet Explorer 6. We have not seen attacks against other affected versions of Internet Explorer. We will continue to monitor the threat environment and update this advisory if this situation changes. On completion of this investigation, Microsoft will take the appropriate action to protect our customers, which may include providing a solution through our monthly security update release process, or an out-of-cycle security update, depending on customer needs.
We are actively working with partners in our Microsoft Active Protections Program (MAPP) and our Microsoft Security Response Alliance (MSRA) programs to provide information that they can use to provide broader protections to customers. In addition, we’re actively working with partners to monitor the threat landscape and take action against malicious sites that attempt to exploit this vulnerability.
Microsoft continues to encourage customers to follow the "Protect Your Computer" guidance of enabling a firewall, applying all software updates and installing anti-virus and anti-spyware software. Additional information can be found at Security at home.
- Protected Mode in Internet Explorer on Windows Vista and later Windows operating systems limits the impact of the vulnerability.
- In a Web-based attack scenario, an attacker could host a Web site that contains a Web page that is used to exploit this vulnerability. In addition, compromised Web sites and Web sites that accept or host user-provided content or advertisements could contain specially crafted content that could exploit this vulnerability. In all cases, however, an attacker would have no way to force users to visit these Web sites. Instead, an attacker would have to convince users to visit the Web site, typically by getting them to click a link in an e-mail message or Instant Messenger message that takes users to the attacker’s Web site.
- An attacker who successfully exploited this vulnerability could gain the same user rights as the local user. Users whose accounts are configured to have fewer user rights on the system could be less affected than users who operate with administrative user rights.
- By default, Internet Explorer on Windows Server 2003 and Windows Server 2008 runs in a restricted mode that is known as Enhanced Security Configuration. This mode sets the security level for the Internet zone to High. This is a mitigating factor for Web sites that you have not added to the Internet Explorer Trusted sites zone.
- By default, all supported versions of Microsoft Outlook, Microsoft Outlook Express, and Windows Mail open HTML e-mail messages in the Restricted sites zone. The Restricted sites zone helps mitigate attacks that could try to exploit this vulnerability by preventing Active Scripting and ActiveX controls from being used when reading HTML e-mail messages. However, if a user clicks a link in an e-mail message, the user could still be vulnerable to exploitation of this vulnerability through the Web-based attack scenario.
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