Rule:

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Sid:
1283

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Summary:
This event is generated when an attempt is made to cause a denial of service of WWW Publishing Service and IIS Administration software.

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Impact:
Denial of service.  This attack may cause a vulnerable server to stop.

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Detailed Information:
Outlook Web Access (OWA) is an optional feature of Microsoft Exchange Server that allows a user to access mail through a web interface supported by Internet Information Services (IIS).  A denial of service of the support software WWW Publishing service and IIS Administration can occur when a user enters a long string of '%' characters in the Log On field in OWA and enters these characcters in the username and password field received in the NT challenge dialog.

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Affected Systems:
Microsoft Exchange Server 5.5 and Microsoft Exchange Server 5.5 SP1, SP2, SP3, SP4

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Attack Scenarios:
An attacker can enter a long string of '%' characters in OWA Log On and challenge fields to cause a denial of service against a vulnerable server.

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Ease of Attack:
Simple.  

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False Positives:
None Known.

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False Negatives:
None Known.

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Corrective Action:
Upgrade to the most current version of Microsoft Exchange Server.

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Contributors:
Original rule writer unknown
Modified by Brian Caswell <bmc@sourcefire.com>
Sourcefire Research Team
Judy Novak <judy.novak@sourcefire.com>

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Additional References:

Bugtraq
http://www.securityfocus.com/bid/3223

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