The Personal Firewall driver (aka epfw.sys) 3.0.672.0 and earlier in ESET Smart Security 3.0.672 and earlier allows local users to gain privileges via a crafted IRP in a certain METHOD_NEITHER IOCTL request to \Device\Epfw that overwrites portions of memory.
https://exchange.xforce.ibmcloud.com/vulnerabilities/47477
http://www.vupen.com/english/advisories/2008/3456
http://www.securityfocus.com/bid/32917
http://www.ntinternals.org/ntiadv0807/ntiadv0807.html
http://www.eset.com/joomla/index.php?option=com_content&task=view&id=4113&Itemid=5