Rule:

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Sid:
1627

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Summary:
This event is generated when packets on the network are using an 
unassigned or reserved IP protocol.

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Impact:
Possible prelude to system compromise.

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Detailed Information:
Under normal circumstances IP packets do not use unassigned or reserved 
protocols.

an indicator of unauthorized network use, reconnaisance activity or 
system compromise. These rules may also generate an event due to 
improperly configured network devices.

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Affected Systems:
	All

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Attack Scenarios:
The attacker may send specially crafted packets using an unassigned or 
reserved protocol.

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Ease of Attack:
Simple

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False Positives:
Research or testing of new protocols may trigger this event.

Novell use protocol 224 for the Cluster heart beat

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False Negatives:
None Known

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Corrective Action:
Use a packet filtering device to reject packets using an unknown 
protocol.

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Contributors:
Original rule writer unknown
Sourcefire Research Team
Nigel Houghton <nigel.houghton@sourcefire.com>

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Additional References:

IANA
http://www.iana.org/assignments/protocol-numbers

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