\Device\NdisTapi (NDISTAPI.sys) in Microsoft Windows XP SP2 and 2003 SP1 uses weak permissions, which allows local users to write to the device and cause a denial of service, as demonstrated by using an IRQL to acquire a spinlock on paged memory via the NdisTapiDispatch function.
https://exchange.xforce.ibmcloud.com/vulnerabilities/33086
http://www.vupen.com/english/advisories/2007/1031
http://www.securityfocus.com/bid/23025
http://www.securityfocus.com/archive/1/463208/100/0/threaded
http://www.reversemode.com/index.php?option=com_remository&Itemid=2&func=fileinfo&id=47