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New MHTML Vulnerability in all versions of Windows

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#1 Romeo29


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Posted 28 January 2011 - 08:50 PM

Microsoft has found new vulnerability in MHTML renderer. The vulnerability exists due to the way MHTML interprets MIME-formatted requests for content blocks within a document. It is possible under certain conditions for this vulnerability to allow an attacker to inject a client-side script in the response of a Web request run in the context of the victim's Internet Explorer. The script could spoof content, disclose information, or take any action that the user could take on the affected Web site on behalf of the targeted user.
Reference : http://www.microsoft.com/technet/security/advisory/2501696.mspx

What is affected?
Internet Explorer and all applications that use it in all the versions of Windows (XP,Vista,7,Server 2003,Server 2008).

Microsoft has released a FixIt tool to lock down MHTML.

How do I open MHT files?
Use Opera which supports MHTML protocol.
Or use Firefox with unMHT add-on. Then associate MHT files with Firefox.

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#2 Budapest


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Posted 31 January 2011 - 07:08 PM

Microsoft has issued a "critical" warning over a newly-discovered flaw in Windows.

In a security advisory, the company warned of a loophole that could be used by malicious hackers to steal private information or hijack computers.

The bug potentially affects every user of the Internet Explorer web browser - around 900 million people worldwide.

The power of accurate observation is commonly called cynicism by those who haven't got it.

—George Bernard Shaw

#3 quietman7


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Posted 03 February 2011 - 01:45 PM

More information about the MHTML Script Injection vulnerability

What would be the side-effect of MHTML lockdown workaround?

In our testing, the only side effect we have encountered is script execution and ActiveX being disabled within MHT documents. We expect that in most environments this will have limited impact. While MHTML is an important component of Windows, it is rarely used via mhtml: hyperlinks. Most often, MHTML is used behind the scenes, and those scenarios would not be impacted by the network protocol lockdown. In fact, if there is no script content in the MHT file, the MHT file would be displayed normally without any issue. Finally, for legitimate MHT files with script content that you would like to be rendered in IE, users can click the information bar and select “Allow All Protocols”,...

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