Microsoft Offers Fix for IE 8 Bug

Thursday, May 9, 2013 @ 02:05 PM gHale


Microsoft released a “Fix it” mitigation for the Internet Explorer 8 vulnerability first found on a sub-site of the U.S. Department of Labor.

This “Fix it” makes a “small change” to mshtml.dll whenever IE 8 loads. Microsoft said a full update to close the hole is currently in the testing process and will be available as soon as it confirms it is ready for all customers.

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Microsoft also notes that EMET is a good workaround for attacks and the “public pentest framework” – presumably a reference to the Metasploit module which exploits the same hole.

The “pentest framework” version of the exploit attempts to target Vista and Windows 7 by making use of a DLL installed by Java 6 to bypass ASLR. The in-the-wild attacks do not do this; Microsoft observed limited attacks targeting IE 8 on Windows XP only, and these end up blocked by EMET’s EAF and anti-ROP mechanisms. The company does, though, still recommend the Fix It as “a stronger level of protection.”

Initial reports suggested the attack was using a known, and patched, vulnerability CVE-2012-4792. It became clear, however, the exploit used was not that one, but a different remote code execution vulnerability.

Microsoft issued an advisory for this vulnerability, CVE-2013-1347, which still only appears in Internet Explorer 8, while it continues its investigation.

The flaw is a use-after-free problem that corrupts memory in such a way as to allow arbitrary code to inject. A Metasploit module is now available that exploits the vulnerability, which means the technique is generally accessible, researchers said.



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