IIS Server May Hang After Processing Several Client Queries

• Microsoft Internet Information Server versions 1.0, 1.0c

SYMPTOMS

The Internet Information Server(IIS) server may stop responding after processing several Universal Resource Locator (URL) requests for an .htm file with additional relational operators as in the following example:

http://www.server.com/default.htm/...and so on...

CAUSE

IIS enters an infinite loop trying to service URL requests for .htm files with additional relational operators. This behavior would eventually result in several server pool threads in infinite loops taking CPU cycles and causing the IIS server to stop responding.

STATUS

Microsoft has confirmed this to be a problem in IIS versions 1.0 and 1.0c. This problem was corrected in the latest Windows NT 3.51 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 

MORE INFORMATION

Comments from bug description:
johnsona and earlier today sampa have found an important issue in iis 1.0c. if you enter a url like http://server/default.htm/.. then it will cause iis to drop into an infinite loop. this is bad because it sucks up threads and cpu cycles and eventually causes the http server to hang because all the threads are spinning. johnson is investigating how to fix it right now. we will likely need to regenerate all the binaries because of this: it is too easy a denial-of-service attack. please plan on executing on this tomorrow morning.

Additional query words: prodiis

Keywords          : kbnetwork kbbug1.00 ntsetup kbfix3.51 NTSrv kbbug1.00c 
Version           : 1.0
Platform          : WINDOWS 
Issue type        : 

Last Reviewed: April 30, 1999