Microsoft Internet Explorer Remote Memory Corruption Vulnerability
2010.January.21

Summary:
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Fortinet's FortiGuard Labs has discovered a memory corruption vulnerability in Microsoft's Internet Explorer.

Impact:
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Remote Code Execution.

Risk:
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Critical

Affected Software:
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For a list of Internet Explorer versions affected, please see the Microsoft Security Advisory reference below.

Additional Information:
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In order to compromise a system / remotely execute code, an attacker would lure a user to a maliciously crafted website. When a user views the Web page, the vulnerability could allow remote code execution. An attacker who successfully exploited this vulnerability could gain the same user rights as the logged-on user. If a user is logged on with administrative user rights, an attacker who successfully exploited this vulnerability could take complete control of an affected system.

Solutions:
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Since an attack scenario would require a user to visit a malicious website, it is recommended to have a layered security solution through webfiltering and intrusion prevention for mitigation.

    * Use the solution provided by Microsoft (MS10-002).
    * FortiGuard Labs released the signature "MS.IE.MergeAttributes.Remote.Code.Execution".
          o Advanced zero-day protection has been available since September 3, 2009.

FortiGuard Labs continues to monitor attacks against this vulnerability.

Fortinet customers who subscribe to Fortinet's intrusion prevention (IPS) service should be protected against this vulnerability. Fortinet's IPS service is one component of FortiGuard Subscription Services, which also offer comprehensive solutions such as antivirus, Web content filtering and antispam capabilities. These services enable protection against threats on both application and network layers. FortiGuard Services are continuously updated by FortiGuard Labs, which enables Fortinet to deliver a combination of multi-layered security intelligence and true zero-day protection from new and emerging threats. These updates are delivered to all FortiGate, FortiMail and FortiClient products. Fortinet strictly follows responsible disclosure guidelines to ensure optimum protection during a threat's lifecycle.

References:
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FortiGuard Advisory: http://www.fortiguard.com/advisory/FGA-2010-05.html
Microsoft Security Bulletin: http://www.microsoft.com/technet/security/bulletin/ms10-002.mspx
CVE ID: http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2010-0247

Acknowledgement:
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Haifei Li of Fortinet's FortiGuard Labs