Symantec symtdi.sys before 7.0.0, as distributed in Symantec AntiVirus Corporate Edition 9 through 10.1 and Client Security 2.0 through 3.1, Norton AntiSpam 2005, and Norton AntiVirus, Internet Security, Personal Firewall, and System Works 2005 and 2006; allows local users to gain privileges via a crafted Interrupt Request Packet (Irp) in an IOCTL 0x83022323 request to \\symTDI\, which results in memory overwrite.