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Microsoft Internet Explorer CreateTextRange Remote Code Execution Vulnerability

Risk
High

Date Discovered
3/22/2006 12:00:00 AM

Description
Microsoft Internet Explorer is susceptible to a remote code-execution vulnerability. This issue is due to a flaw that results in an invalid table-pointer dereference. Remote attackers may exploit this issue to crash affected browsers or to execute arbitrary machine code in the context of affected users. Microsoft has reported that this issue does not affect the March 20, 2006 release of Internet Explorer 7 Beta 2 Preview.

Symantec Vulnerability Assessment

Symantec Vulnerability Assessment detects and reports this vulnerability. Click here for the advisory released April 19, 2006.

Symantec Enterprise Security Manager Network Assessment Module
Symantec Enterprise Security Manager Network Assessment Module detects and reports this vulnerability. Click here for the advisory released April 18, 2006.

Technologies Affected
Microsoft Internet Explorer 7.0 beta2
Microsoft Internet Explorer 6.0
Microsoft Internet Explorer 6.0 SP1
Microsoft Internet Explorer 5.0.1 SP1
Microsoft Internet Explorer 5.0.1 SP2
Microsoft Internet Explorer 5.0.1 SP4
Microsoft Internet Explorer 6.0 SP2
Microsoft Internet Explorer 5.0.1 SP3

Recommendations
Do not follow links provided by unknown or untrusted sources.
Do not visit websites of unknown or questionable integrity from production systems.
Set web browser security to disable the execution of JavaScript.
Since the exploitation of this issue requires executing malicious script code in web clients, consider disabling support for script code and active content within a client browser. Note that this mitigation tactic might adversely affect legitimate websites that rely on the execution of browser-based script code.
Implement multiple redundant layers of security.
Various memory-protection schemes (such as non-executable and randomly mapped memory segments) may hinder an attacker's ability to exploit this vulnerability to execute arbitrary code.
Run all software as a non-privileged user with minimal access rights.
Due to the potential for arbitrary code execution, run the browser as an unprivileged user with minimal access rights. This will limit the consequences of exploitation.

The Internet Explorer 7 Beta 2 Preview released on March 20, 2006 is not affected by this vulnerability. Users of earlier Internet Explorer 7 beta releases are advised to upgrade. Updates are not currently available for other Internet Explorer releases. Microsoft has released a cumulative update to address this issue. Please see the referenced advisories for further information.
Microsoft Internet Explorer 5.0.1 for Windows 2000:

Microsoft Patch Cumulative Update for Internet Explorer 5.01 Service Pack 4 (KB912812)
http://www.microsoft.com/downloads/details.aspx?familyid=594E7B87-AF8F-4346-9164-596E3E5C22B1&displaylang=en

Microsoft Internet Explorer 6.0 SP1:
Microsoft Patch Cumulative Update for Internet Explorer 6 SP1 (KB912812)
http://www.microsoft.com/downloads/details.aspx?familyid=033C41E1-2B36-4696-987A-099FC57E0129&displaylang=en

Microsoft Internet Explorer 6.0:
Microsoft Patch Cumulative Update for Internet Explorer 6 SP1 (KB912812)
http://www.microsoft.com/downloads/details.aspx?familyid=033C41E1-2B36-4696-987A-099FC57E0129&displaylang=en
Microsoft Patch Cumulative Update for Internet Explorer for Windows XP Service Pack 2 (KB912812)
http://www.microsoft.com/downloads/details.aspx?familyid=F05FFB31-E6B4-4771-81F1-4ACCEBF72133&displaylang=en

Microsoft Internet Explorer 6.0 SP2:
Microsoft Patch Cumulative Update for Internet Explorer for Windows XP Service Pack 2 (KB912812)
http://www.microsoft.com/downloads/details.aspx?familyid=F05FFB31-E6B4-4771-81F1-4ACCEBF72133&displaylang=en

Microsoft Internet Explorer 6.0:
Microsoft Patch Cumulative Update for Internet Explorer for Windows Server 2003 (KB912812)
http://www.microsoft.com/downloads/details.aspx?familyid=EE566871-D217-41D3-BECC-B27FAFA00054&displaylang=en
Microsoft Patch Cumulative Update for Internet Explorer for Windows Server 2003 64-bit Itanium Edition (KB912812) -
http://www.microsoft.com/downloads/details.aspx?familyid=E584957C-0ABE-4129-ABAF-AA2852AD62A3&displaylang=en
Microsoft Patch Cumulative Update for Internet Explorer for Windows Server 2003 x64 Edition (KB912812) - English
http://www.microsoft.com/downloads/details.aspx?familyid=5A1C8BE3-39EE-4937-9BD1-280FC35125C6&displaylang=en
Microsoft Patch Cumulative Update for Internet Explorer for Windows XP x64 Edition (KB912812)
http://www.microsoft.com/downloads/details.aspx?familyid=C278FE3E-620A-4BBC-868B-CA2D9EFF7AC3&displaylang=en

References
Source: Internet Explorer Home Page
URL: http://www.microsoft.com/windows/ie/default.mspx

Source: Microsoft Internet Explorer (mshtml.dll) Remote Code Execution
URL: http://www.computerterrorism.com/research/ct22-03-2006

Source: Microsoft Security Advisory (917077)
URL: http://www.microsoft.com/technet/security/advisory/917077.mspx

Source: Microsoft Security Bulletin MS06-013
URL: http://www.microsoft.com/technet/security/Bulletin/MS06-013.mspx

Source: Microsoft Technet Security
URL: http://www.microsoft.com/technet/security

Credits
Discovered by Joshua Heyer.


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