Patch is Available (Re: Microsoft IIS 5.0 Web Server Can Be Restarted Remotely By Any User)
SecurityTracker Alert ID: 1001095|
SecurityTracker URL: http://securitytracker.com/id/1001095
(Links to External Site)
Date: Mar 15 2001
Denial of service via network|
Fix Available: Yes Vendor Confirmed: Yes |
Georgi Guninski reports a vulnerability with Microsoft's Internet Information Server (IIS) v5.0 in which a remote user can send a certain packet to the server, causing the server to automatically restart|
The vendor has released a revised advisory (Bulletin: MS01-0016) to announce that a patch is now available.
The vendor recommends using the patch rather than the workaround described in a previous advisory.
A remote user with access to the web server's port (which is basically everyone in the case of a public web server) can cause the server to crash and restart.|
The vendor has released a patch. The vendor recommends using the patch rather than the workaround described in a previous advisory.|
Vendor URL: www.microsoft.com/technet/security/bulletin/MS01-016.asp (Links to External Site)
Boundary error, State error|
|Underlying OS: Windows (2000)|
This archive entry is a follow-up to the message listed below.|
Source Message Contents
Subject: Microsoft Security Bulletin MS01-016 (version 2.0)|
The following is a Security Bulletin from the Microsoft Product Security
Please do not reply to this message, as it was sent from an unattended
-----BEGIN PGP SIGNED MESSAGE-----
Title: Malformed WebDAV Request Can Cause IIS
to Exhaust CPU Resources
Released: 08 March 2001
Revised: 13 March 2001 (version 2.0)
Software: IIS 5.0
Impact: Denial of Service
Microsoft encourages customers to review the Security Bulletin at:
Reason for Revision:
The original version of this bulletin provided a workaround
(discussed in Knowledge Base article Q241520) that would protect
affected systems by disabling WebDAV services. However, a security
patch is now available that eliminates the vulnerability, and
Microsoft recommends using the patch rather than the workaround. We
have updated both the bulletin and the narrative below to reflect
WebDAV is an extension to the HTTP protocol that allows remote
authoring and management of web content. In the Windows 2000
implementation of the protocol, IIS 5.0 performs initial processing
of all WebDAV requests, then forwards the appropriate commands to the
WebDAV process. However, a flaw exists in the way WebDAV handles a
particular type of malformed request. If a stream of such requests
were directed at an affected server, it would consume all CPU
availability on the server.
The patch should be applied to all machines running IIS 5.0. While
this obviously includes web servers, it's worth noting that IIS 5.0
may be running on other types of servers as well, particularly mail
servers running Exchange 2000.
- The effect of an attack via this vulnerability would be
temporary. The server would automatically resume normal
service as soon as the malformed requests stopped arriving.
- The vulnerability does not provide an attacker with any
capability to carry out WebDAV requests.
- The vulnerability does not provide any capability to
compromise data on the server or gain administrative
control over it.
- A patch is available to fix this vulnerability. Please read the
for information on obtaining this patch.
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