Microsoft Windows NT 4.0, Windows 2000, Windows XP, and Windows Small Business Server 2003 allow remote attackers to cause a denial of service (IP stack hang) via a continuous stream of packets on TCP port 135 that have incorrect TCP header checksums and random numbers in certain TCP header fields, as demonstrated by the Achilles Windows Attack Tool. NOTE: the researcher reports that the Microsoft Security Response Center has stated "Our investigation which has included code review, review of the TCPDump, and attempts on reproing the issue on multiple fresh installs of various Windows Operating Systems have all resulted in non confirmation.