There are many trends and developments made that have been made in the recent years that help minimize the threat of zero-day attacks. One of these developments is simply called ‘zero-day protection’. This is simply the ability to protect against zero-day exploits. It entirely relies on knowing when a particular venerability is going to occur ahead of time, therefore creating signatures in case of any attempt to take advantage of the vulnerability.
In addition, buffer overflow is another development that has been created to limit the effectiveness of zero-day memory corruption risks. It is a programming error that has a few factors behind it, one of them being a possible breach in the security system. Latest operating systems have these zero-day protections built-in in them, such as Mac OS X, Microsoft Windows Vista, Linux, UNIX, and Sun Microsystems Solaris.
Adding onto that, the legitimate trade programs of zero-day code software encourages the talented hackers to use their skills to help detect dangers and improve security of loopholes instead of taking advantage of it.
On the contrary, these protections are not guaranteed. A worm good enough could manage to fit itself through a small time window between the discovery of vulnerability and the release of a new worm trying to take advantage of it.