Rule:  

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Sid:
3000

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Summary:
This event is generated when an attempt is made to exploit a known 
vulnerability in the Microsoft implementation of the ASN.1 Library.

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Impact:
Serious. Execution of arbitrary code, DoS.

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Detailed Information:
A buffer overflow condition in the Microsoft implementation of the ASN.1 
Library. It may be possible for an attacker to exploit this condition by 
sending specially crafted authentication packets to a host running a 
vulnerable operating system.

When the taget system decodes the ASN.1 data, exploit code may be included 
in the data that may be excuted on the host with system level privileges. 
Alternatively, the malformed data may cause the service to become 
unresponsive thus causing the DoS condition to occur.

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Affected Systems:
	Microsoft Windows NT
	Microsoft Windows NT Terminal Server Edition
	Microsoft Windows 2000
	Microsoft Windows XP
	Microsoft Windows 2003

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Ease of Attack:
Simple. Exploit code exists.

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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 patches.

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Contributors:
Sourcefire Research Team
Brian Caswell <bmc@sourcefire.com>
Nigel Houghton <nigel.houghton@sourcefire.com>

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Additional References:

Microsoft:
http://www.microsoft.com/security/encyclopedia/details.aspx?name=win32/rbot

US-CERT
http://www.us-cert.gov/cas/techalerts/TA04-041A.html

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