The Trend Micro AntiVirus scan engine before 8.550-1001 as used in Trend Micro PC-Cillin Internet Security 2007 and Tmxpflt.sys 8.320.1004 and 8.500.0.1002 has weak permissions (Everyone:Write) for the \\\\.\\Tmfilter device which allows local users to send arbitrary content to the device via the IOCTL functionality. NOTE: this can be leveraged for privilege escalation by exploiting a buffer overflow in the handler for IOCTL 0xa0284403.