SOURCES:
Microsoft Internet Explorer Use-After-Free Vulnerability Guidance | US-CERT
AND
Vulnerability Note VU#222929 - Microsoft Internet Explorer use-after-free vulnerability
Microsoft Internet Explorer Use-After-Free Vulnerability Guidance
Original release date: April 28, 2014
US-CERT is aware of active exploitation of a use-after-free vulnerability in Microsoft Internet Explorer. This vulnerability affects IE versions 6 through 11 and could allow unauthorized remote code execution.
US-CERT recommends that users and administrators review Microsoft Security Advisory 2963983 for mitigation actions and workarounds. Those who cannot follow Microsoft's recommendations, such as Windows XP users, may consider employing an alternate browser.
For more details, please see VU#222929.
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Vulnerability Note VU#222929
Microsoft Internet Explorer use-after-free vulnerability
Original Release date: 27 Apr 2014 | Last revised: 28 Apr 2014
Overview
Microsoft Internet Explorer contains a use-after-free vulnerability, which can allow a remote, unauthenticated attacker to execute arbitrary code on a vulnerable system.
Description
Microsoft Internet Explorer contains a use-after-free vulnerability. This can allow for arbitrary code execution. Internet Explorer versions 6 through 11 are affected.
Note that this vulnerability is being exploited in the wild. Although no Adobe Flash vulnerability appears to be at play here, the Internet Explorer vulnerability is used to corrupt Flash content in a way that allows ASLR to be bypassed via a memory address leak. This is made possible with Internet Explorer because Flash runs within the same process space as the browser. Note that exploitation without the use of Flash may be possible.
Impact
By convincing a user to view a specially crafted HTML document (e.g., a web page or an HTML email message or attachment), an attacker may be able to execute arbitrary code.
Solution
We are currently unaware of a practical solution to this problem. Please see Microsoft Security Advisory 2963983 for workarounds. Please also consider the following workarounds:
Use the Microsoft Enhanced Mitigation Experience Toolkit
The Microsoft Enhanced Mitigation Experience Toolkit (EMET) can be used to help prevent exploitation of this vulnerability. Note that platforms that do not support ASLR, such as Windows XP and Windows Server 2003, will not receive the same level of protection that modern Windows platforms will.