Rule:

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Sid:
365

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Summary:
This event is generated when an external user pings an internal server using an echo request ICMP type. This may indicate an attempt to scan the network or cause a denial of service using a "ping flood." 

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Impact:
Possible information gathering or denial of service attempt. 

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Detailed Information:
An ICMP ping may indicate a scanning attempt, a ping flood, or a remote user attempting to see if the network responds.

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Affected Systems:
Any system that responds to a ping request.

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Attack Scenarios:
An attacker can use a scanner that pings a system to find out more information about the network, or the attacker can use a tool to send a large number of pings in an attempt to "flood" the network and create a denial of service condition.

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Ease of Attack:
Simple. Scanning and ping-based DoS tools are freely available.

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False Positives:
This rule will generate an alert if a legitimate remote user pings an internal server.

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False Negatives:
None known.

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Corrective Action:
Use a packet filtering firewall to block ICMP ping packets with an ICMP type value of 8.

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Contributors:
Original rule writer unknown.
Sourcefire Research Team
Sourcefire Technical Publications Team
Jen Harvey <jennifer.harvey@sourcefire.com>

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Additional References:


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