Rule: 

--
Sid: 
111-1

-- 
Summary: 
This event is generated when the pre-processor stream4
detects network traffic that may constitute an attack.

-- 
Impact: 
This may indicate scanning activity.

--
Detailed Information:
The pre-processor stream4 has detected network traffic that may indicate
a network scan is in progress. That is, a TCP datastream has been
detected that does not conform to normal activity.

An attacker may be able to determine the characteristics of a remote
system by sending abnormal network data. The response can reveal the
operating system type, indicate the presence of a firewall or show open
and closed ports on the host.

--
Affected Systems:
	All systems

--
Attack Scenarios: 
An attacker may utilize scanning techniques to determine possible points
of exploitation against a host.

-- 
Ease of Attack: 
Simple. Many scanning tools exist.

-- 
False Positives:
None Known.

--
False Negatives:
None Known.

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

Ensure the system is up to date with any appropriate vendor supplied patches.

--
Contributors:
Martin Roesch <roesch@sourcefire.com>
Sourcefire Vulnerability Research Team
Nigel Houghton <nigel.houghton@sourcefire.com>

-- 
Additional References:

--