Rule: 

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Sid: 
120-1

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Summary: 
This event is generated when the pre-processor http_inspect
detects network traffic that may constitute an attack.

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Impact: 
Unknown.

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Detailed Information:
This event is generated when the http_inspect pre-processor detects the
presence of a web server running on a non-defined port.

Web server ports are defined in snort.conf as the variable $HTTP_PORTS
and also in the section for http_inspect. When a server is accessed on a
port not defined in snort.conf the presence of web traffic generates an
event. This may indicate the presence of an unauthorized web server.

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Affected Systems:
	All.

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Attack Scenarios: 
A web server may be used to transfer files from inside the protected
network to unauthorized recipients on the outside.

-- 
Ease of Attack: 
Simple.

-- 
False Positives:
None Known.

--
False Negatives:
None Known.

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Corrective Action:
Check the target host for signs of compromise.

Apply any appropriate vendor supplied patches.

--
Contributors: 
Daniel Roelker <droelker@sourcefire.com>
Sourcefire Vulnerability Research Team
Nigel Houghton <nigel.houghton@sourcefire.com>

-- 
Additional References:

HTTP IDS Evasions Revisited - Daniel Roelker
http://docs.idsresearch.org/http_ids_evasions.pdf

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