The Server Message Block (SMB) driver (MRXSMB.SYS) in Microsoft Windows 2000 SP4, XP SP1 and SP2, and Server 2003 SP1 and earlier allows local users to execute arbitrary code by calling the MrxSmbCscIoctlOpenForCopyChunk function with the METHOD_NEITHER method flag and an arbitrary address, possibly for kernel memory, aka the "SMB Driver Elevation of Privilege Vulnerability."