Microsoft has released a fix for a flaw that enabled Stuxnet to exploit. The fix addresses a problem with a patch released in 2010, which left users exposed to one of the core vulnerabilities that enabled the worm. Microsoft’s MS15-020 (rated critical by Microsoft) impacts all supported versions of Windows, from Vista and Windows Server 2003 to Windows 8.1 and Server 2012 R2. The worm targeted zero-day flaws in Windows, as well as PLCs (programmable logic controllers) in Iran.”]