Rule:

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Sid:
252

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Summary:
This event is generated when an attempt is made to send an inverse query
to a DNS server. This could indicate a future attack.

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Impact:
Intelligence gathering. This is just an attempt to see if the DNS server
responds to such a query.

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Detailed Information:
Certain versions of BIND fail to propery bound data recieved when 
handling an inverse query. Upon being copied to memory, portions of the 
program can be overwritten and arbitrary commands can be run on the 
affected host.

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Affected Systems:
	BIND pre 8.1.2 / 4.9.8

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Attack Scenarios:
An attacker can send the reverse query and if the server responds the 
attacker might then proceed to exploit the flaw in Bind.

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Ease of Attack:
Simple. Exploit code is available.

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False Positives:
None Known

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False Negatives:
None Known

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Corrective Action:
Upgrade BIND.

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Contributors:
Original Rule Writer Unknown
Sourcefire Research Team
Nigel Houghton <nigel.houghton@sourcefire.com>
Snort documentation contributed by Josh Sakofsky

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Additional References:

RFC:
http://www.rfc-editor.org/rfc/rfc1035.txt

Bugtraq:
http://www.securityfocus.com/bid/134

CVE:
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-1999-0009

Arachnids:
http://www.whitehats.com/info/IDS277 

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