Internet Storm Center issued a rare one day YELLOW ALERT to promote awareness of IE exploits circulating in the wild.

https://isc.sans.edu/diary/Threat+Level+Yellow%3A+Protection+recommendations+regarding+Internet+Explorer+exploits+in+the+wild/16634

http://www.fireeye.com/blog/technical/cyber-exploits/2013/09/operation-deputydog-zero-day-cve-2013-3893-attack-against-japanese-targets.html

QUOTE: The Internet Storm Center is beginning to see increased evidence of exploits in the wild regarding Microsoft Security Advisory 2887505.  Accordingly, we’re moving the InfoCon up to Yellow.  Microsoft is investigating public reports of a vulnerability in all supported versions of Internet Explorer. Microsoft is aware of targeted attacks that attempt to exploit this vulnerability in Internet Explorer 8 and Internet Explorer 9. Applying the Microsoft Fix it solution, CVE-2013-3893 Fix It Workaround, prevents the exploitation of this issue. This FixIt solution also includes EMET 4.0 guidance.