Microsoft ASP.NET fails to perform proper canonicalization

Overview

Microsoft ASP.NET contains a canonicalization vulnerability that may allow a remote unauthenticated attacker to gain access to secure contents.

Description

Microsoft ASP.NET is a programming framework for creating web applications. The canonicalization routine used by ASP.NET fails to correctly parse URLs.

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Impact

Depending on the contents of the web site, an attacker may take a variety of actions. For example, a remote unauthenticated attacker may be able to access secure web site contents by using a specially crafted URL.

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Solution

Install an update

Install an update, as specified by MS05-004.

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Workarounds

Microsoft includes the following workarounds in MS05-004:

* Install an HTTP module to check for canonicalization issues as described in Microsoft Knowledge Base article [87289](<http://support.microsoft.com/kb/887289>).
* Test for canonicalization issues with ASP.NET as described in Microsoft Knowledge Base article [887459](<http://support.microsoft.com/kb/887459>).
* Install and use [URLScan](<http://www.microsoft.com/windows2000/downloads/recommended/urlscan/default.asp>).  

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Vendor Information

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Avaya __ Affected

Updated: February 17, 2005

Status

Affected

Vendor Statement

We have not received a statement from the vendor.

Vendor Information

The vendor has not provided us with any further information regarding this vulnerability.

Addendum

Please see the Avaya Security Advisory.

If you have feedback, comments, or additional information about this vulnerability, please send us [email](<mailto:[email protected]?Subject=VU%23283646 Feedback>).

Microsoft Corporation __ Affected

Updated: February 08, 2005

Status

Affected

Vendor Statement

We have not received a statement from the vendor.

Vendor Information

The vendor has not provided us with any further information regarding this vulnerability.

Addendum

Please see MS05-004.

If you have feedback, comments, or additional information about this vulnerability, please send us [email](<mailto:[email protected]?Subject=VU%23283646 Feedback>).

CVSS Metrics

Group	Score	Vector
Base
Temporal
Environmental

References

• <http://www.microsoft.com/technet/security/bulletin/ms05-004.mspx&gt;
• <http://www.microsoft.com/protect/computer/updates/bulletins/200710.mspx&gt;
• <http://www.microsoft.com/windows2000/downloads/recommended/urlscan/default.asp&gt;
• <http://support.microsoft.com/kb/887289&gt;
• <http://support.microsoft.com/kb/887459&gt;
• <http://archives.neohapsis.com/archives/ntbugtraq/2004-q3/0221.html&gt;
• <http://xforce.iss.net/xforce/xfdb/17644&gt;
• <http://www.securityfocus.com/bid/11342&gt;
• <http://secunia.com/advisories/12749/&gt;
• <http://securitytracker.com/alerts/2004/Oct/1011559.html&gt;
• <http://securitytracker.com/alerts/2005/Feb/1013109.html&gt;

Acknowledgements

This vulnerability was publicly disclosed by Toby Beaumont.

This document was written by Will Dormann.

Other Information

CVE IDs:	CVE-2004-0847
Severity Metric:	37.97 Date Public: