Vulnerability Note VU#222929

Microsoft Internet Explorer use-after-free vulnerability

Original Release date: 27 Apr 2014 | Last revised: 29 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:

Unregister VMX.DLLMicrosoft provides guidance to unregister VMX.DLL:

Click Start, click Run, type “%SystemRoot%\System32\regsvr32.exe” -u “%CommonProgramFiles%\Microsoft Shared\VGX\vgx.dll”, and then click OK.
A dialog box appears to confirm that the un-registration process has succeeded. Click OK to close the dialog box.

The Microsoft Security Advisory fails to mention whether the vulnerabilities lies within VMX.DLL, or whether VMX.DLL is simply used in the exploits in the wild, though.

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.

Vendor Information (Learn More)

Vendor	Status	Date Notified	Date Updated
Microsoft Corporation	Affected	–	27 Apr 2014

If you are a vendor and your product is affected, let us know.

CVSS Metrics (Learn More)

Group	Score	Vector
Base	10.0	AV:N/AC:L/Au:N/C:C/I:C/A:C
Temporal	9.5	E:H/RL:W/RC:C
Environmental	9.5	CDP:ND/TD:H/CR:ND/IR:ND/AR:ND

References

Credit

This vulnerability was publicly reported by FireEye

This document was written by Will Dormann.

Other Information

CVE IDs: CVE-2014-1776
Date Public: 26 Apr 2014
Date First Published: 27 Apr 2014
Date Last Updated: 29 Apr 2014
Document Revision: 15

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More info HERE