Vulnerability in Internet Explorer 8 Could Allow Remote Code Execution

ITS Advisory Number: 
2014-049
Date(s) Issued: 
Tuesday, May 27, 2014
Subject: 
Vulnerability in Internet Explorer 8 Could Allow Remote Code Execution
Overview: 

A vulnerability has been discovered in Microsofts web browser, Internet Explorer, which could allow an attacker to take complete control of an affected system. Successful exploitation of this vulnerability could result in an attacker gaining the same privileges as the logged on user. Depending on the privileges associated with the user, an attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. 

It should be noted that there is currently no patch available for this vulnerability. 

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Systems Affected: 
  • Microsoft Internet Explorer 8
RISK
GOVERNMENT
Large and medium government entities: 
High
Small government entities: 
High
BUSINESS
Large and medium business entities: 
High
Small business entities: 
High
Home Users: 
High
Description: 

A vulnerability has been reported affecting version 8 of Internet Explorer that could allow for remote code execution. This vulnerability exists due to the way that Internet Explorer handles CMarkup objects.

Specifically this issue occurs when freeing a CMarkup object from memory after the execution of certain JavaScript code followed by a CollectGarbage call. By manipulating a documents elements an attacker can force a dangling pointer to be reused after it has been freed. An attacker can leverage this vulnerability to execute code under the context of the current process. This vulnerability can be exploited by a user visiting a specially crafted website.

Successful exploitation of this vulnerability could result in an attacker gaining the same privileges as the logged on user. Depending on the privileges associated with the user, an attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

It should be noted that there is currently no patch available for this vulnerability.   

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Actions: 
  • Consider upgrading to the latest version of Internet Explorer or use an alternate browser until a patch is made available.
  • Consider implementing Microsofts Enhanced Mitigation Experience Toolkit (EMET) as it has been reported to make the vulnerability difficult to exploit.
  • Run Internet Explorer with Protected Mode enabled.
  • Consider setting Internet and Local Intranet Security Zone settings to "High"
  • Remind users not to visit un-trusted websites or follow links provided by unknown or un-trusted sources.
  • Run all software as a non-privileged user (one without administrative privileges) to diminish the effects of a successful attack.
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References: 
Microsoft:
http://support.microsoft.com/kb/2909257/en-us
http://support.microsoft.com/kb/2458544
Security Focus:
http://www.securityfocus.com/bid/67544
TippingPoint Zero Day Initiative:
http://zerodayinitiative.com/advisories/ZDI-14-140/
CVE:
http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-1770