Telnet to Port 135 Causes 100 Percent CPU Usage

ID: Q162567

The information in this article applies to:

Microsoft Windows NT Workstation versions 3.51, 4.0
Microsoft Windows NT Server versions 3.51, 4.0

SYMPTOMS

When a client uses the telnet utility to connect to port 135 of a computer running Windows NT Server, and then types more than 10 random characters and disconnects, the server CPU usage jumps to 100 percent and does not come back down until the server is restarted.

CAUSE

This problem is caused by a problem with the remote procedure call (RPC) components in Windows NT.

RESOLUTION

To resolve this problem, download and install the appropriate file:

Windows NT 3.51

This hotfix has been posted to the following Internet location:

ftp://ftp.microsoft.com/bussys/winnt/winnt-public/fixes/usa/NT351/hotfixes-postSP5/rpc-fix

Windows NT 4.0

This hotfix has been posted to the following Internet location:

ftp://ftp.microsoft.com/bussys/winnt/winnt-public/fixes/usa/NT40/hotfixes-postSP2/rpc-fix

STATUS

Microsoft has confirmed this problem could result in some degree of security vulnerability in Windows NT version 4.0. This problem was corrected in the latest Microsoft Windows NT 4.0 U.S. Service Pack. For information on obtaining the service pack, query on the following word in the Microsoft Knowledge Base (without the spaces):

S E R V P A C K

Microsoft has confirmed this problem could result in some degree of security vulnerability in Windows NT version 3.51. A fully supported fix is now available, but it has not been fully regression tested and should only be applied to systems determined to be at risk of attack. Please evaluate your system's physical accessibility, network and Internet connectivity, and other factors to determine the degree of risk to your system. If your system is sufficiently at risk, Microsoft recommends you apply this fix. Otherwise, wait for the next Windows NT service pack, which will contain this fix. Please contact Microsoft Technical Support for more information.

Additional query words: Telnet RPC crash hang max prodnt

Keywords : kbnetwork kbbug4.00 nttcp kbbug3.51 kbfix4.00.sp3 NTSrvWkst
Version : 3.51 4.0
Platform : winnt
Issue type : kbbug