Windows Updates-TCP/IP, DUN & Winsock
By sending fragmented IGMP packets to a Windows 95, 98 or Windows NT machine, it is possible to disrupt normal operations, varying from slowing performance to crashing the operating system. A series of fragmented IGMP packets causes the affected system to access invalid memory, which either causes some services to fail ( called "denial of service" ) or the machine to crash altogther. This can happen under normal circumstances on a network, or might be initiated by an attacker with the specific intention of crashing the machine. This patch installs the newest version of the "vip.386" file. Windows NT has other mechanisms, that make this type of attack more difficult and is not as liable as Windows 95 or 98. This update eliminates the vulnerability in Microsoft's implementation of TCP/IP.
Update for Windows 98 Second Edition