This new Security Response blog post will be of interest to followers of this thread:

2013 First Quarter Zero-Day Vulnerabilities
https://www-secure.symantec.com/connect/blogs/2013-first-quarter-zero-day-vulnerabilities

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Symantec recommends users to follow these best security practices:

• Ensure all applications are up to date with the latest security patches. Even though a zero-day exploit cannot be patched, the latest updates will provide protection from previously disclosed vulnerabilities.
• Ensure antivirus and IPS definitions are up-to-date.
• Avoid visiting sites of questionable integrity.
• Avoid opening files provided by untrusted sources.
• Implement multiple redundant layers of security such as non-executable and randomly mapped memory segments that may hinder an attacker's ability to exploit vulnerabilities.