Remote DoS attack in Internet Information Server 4.0 & 5.0 Vulnerability



Internet Information Server 4.0 & 5.0

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USSR Advisory Code:   USSR-2000040

Release Date:
May 11, 2000

Affected Software Versions:

Microsoft Internet Information Server 4.0
Microsoft Internet Information Server 5.0 


The Ussr Labs team has recently discovered a memory problem in IIs 4.0 and 5.0. 
What happens is by preforming an attack with specially-malformed information extension data in The URL,
it will cause slow the performance of an affected server, or temporarily stop it altogether.

SPECIAL NOTE: That we take no responsibility for this code it is for educational purposes only.

Vendor Status:

Contacted: Saturday, April 15, 2000 7:12 AM

Vendor   Url:
Program  Url: (IIS 4.0)
Program  Url: (IIS 5.0)


Internet Information Server 4.0:

Internet Information Server 5.0:

More Information: 

Microsoft Security Bulletin MS00-021: Frequently Asked Questions, 

Microsoft Knowledge Base article Q260205 discusses this issue and will be available soon

Related Links:

Underground Security Systems Research

Eeye, Attrition, w00w00, beavuh, Rhino9,, ADM, HNN, Sub, Technotronic and Wiretrip.

Copyright (c) 1999-2000 Underground Security Systems Research.
Permission is hereby granted for the redistribution of this alert electronically. It is not to be 
edited in any way without express consent of Ussr. If you wish to reprint the whole or any part of 
this alert in any other medium excluding electronic medium, please e-mail for 

The information within this paper may change without notice. Use of this information constitutes 
acceptance for use in an AS IS condition. There are NO warranties with regard to this information. 
In no event shall the author be liable for any damages whatsoever arising out of or in connection 
with the use or spread of this information. Any use of this information is at the user's own risk.

Please send suggestions, updates, and comments to:

Underground Security Systems Research