Rule:  

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Sid:
256

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Summary:
This event is generated when an attempt is made to query authors.bind chaos 
record on a DNS server.  

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Impact:
Information gathering. This activity may indicate reconnaisance before 
an impending attack.

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Detailed Information:
Bind 9.x allows you get the authors.bind chaos record.  The ability to
retrieve this file indicates that the machine is running at least a
9.x variant of the bind nameserver.

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Affected Systems:
	All DNS Servers using Bind
 
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Attack Scenarios:
As part of a reconnaissance mission, an attacker may attempt to glean
important information about network infrastructure by determining the
bind version on a nameserver. If authors.bind is retrievable, this
indicates that Bind 9.x is in use.

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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:
Remove the ability to retrieve the authors.bind chaos record by changing 
the DNS configuration accordingly.

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Contributors:
Original rule writer unknown
Snort documentation contributed by Jon Hart <warchild@spoofed.org>
Sourcefire Vulnerability Research Team
Nigel Houghton <nigel.houghton@sourcefire.com>

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Additional References:

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