Microsoft Windows NT 4.0 Security Patch and Windows 95/98/98SE/ME Workaround : 'Incomplete TCP/IP Packet' Vulnerability

There is a denial of service vulnerability that affects Windows NT 4.0 Windows 95, 98, 98 Second Edition and Windows Me. (Windows 2000 is not affected by this vulnerability.) By sending a flood of specially malformed TCP/IP packets to a victim’s machine a malicious user could cause either of two effects. In the most likely case, the flood would temporarily prevent any networking resources on an affected computer from responding to client requests; as soon as the packets stopped arriving, the machine would resume normal operation. In a less likely case, the system could hang, and remain unresponsive until it was rebooted.This vulnerability could only be exploited if TCP port 139 was open on the target machine. If the server service or File/Print sharing were disabled on a computer it would not be susceptible to this vulnerability.USERS OF WINDOWS NT 4.0: The patch has been tested on a Windows NT 4.0 computer with Service Pack 6a. Simply download and install the patch.USERS OF WINDOWS 98/98SE/ME: Do *not* download or install this patch. All you need to do is disable File And Printer Sharing component for your Dial-Up adapter. Here's how: Open up your Control Panel from the Start Menu (click Start | Settings | Control Panel); double-click the Network applet; select TCP/IP Dial-up Adapter in the menu; click the Properties button; click the Bindings tab; uncheck the File And Printer Sharing check box; click OK; click OK again. Repeat this process of you have more than one TCP/IP Dial-up Adapters. Restart the computer. (Note: This disables the File And Printer Sharing component only for the Dial-Up Networking adapter. Local network file sharing or printer sharing is not affected.)USERS OF WINDOWS 95: Do *not* download or install this patch. All you need to do is disable File And Printer Sharing component for your Dial-Up adapter. Here's how: Open up your Control Panel from the Start Menu (click Start | Settings | Control Panel); double-click the Network applet; click the File And Print Sharing… button; uncheck both check boxes; click OK; click OK again. Restart the computer.