Rule:

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Sid:

1768 

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Summary:
This event is generated when an attempt is made to overflow a buffer in HTTP header field handler of Microsoft Internet Information Server (IIS) versions 4.0, 5.0, and 5.1.

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Impact:
Denial of Service, arbitrary code execution. Full administrative control is possible.

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Detailed Information:
A vulnerability exists in HTTP header process in ASP.DLL , a specially crafted packet sent to this processor will allow an attacker to disrupt the ISS service or run any arbitrary commands with the privileges of the ASP ISAPI extension.

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Affected Systems:
	Microsoft Internet Information Server 4.0 
	Microsoft Internet Information Services 5.0 
	Microsoft Internet Information Services 5.1 

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Attack Scenarios:
A remote attacker first probes the version of ISS server then ,could attempt overflow one of the HTTP header field buffers and execute arbitrary code on the system.

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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:
Apply the appropriate vendor supplied patch.

Upgrade to the latest non-affected version of the software.

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Contributors:
Sourcefire Research Team
Brian Caswell <bmc@sourcefire.com>
Nigel Houghton <nigel.houghton@sourcefire.com>
Snort documentation contributed by Nawapong Nakjang (tony@ksc.net, tonie@thai.com)

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Additional References:

Microsoft:
http://www.microsoft.com/technet/security/bulletin/MS02-018.asp

CERT:
http://www.cert.org/advisories/CA-2002-09.html

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