Rule:

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Sid:
240

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Summary:
This event is generated when a DDoS Shaft agent communicates with a Shaft handler.  It is also possible that this event may be generated when any host attempts to discover a Shaft handler.   

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Impact:
Attempted DDoS. If the listed source IP is in your network, it may be a Shaft agent or a host attempting to discover Shaft handlers.  If the listed destination IP is in your network, it may be a Shaft handler.

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Detailed Information:
The Shaft DDoS uses a tiered structure of compromised hosts to coordinate and participate in a distributed denial of service attack. Handlers communicate with agents to direct them to launch attacks. An agent may communicate with a handler using a UDP packet to destination port 20433 with a content of "alive".

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Affected Systems:
Any Shaft compromised host.

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Attack Scenarios:
A Shaft agent needs to communicate with a handler before it is given directions to launch an attack. 

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Ease of Attack:
Simple. Shaft code is freely available.

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False Positives:
None Known.

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False Negatives:
None Known.

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Corrective Action:
Perform proper forensic analysis on the suspected compromised host to discover the means of compromise.

Rebuild a confirmed compromised host.

Use a packet-filtering firewall to block inappropriate traffic to the network to prevent hosts from being compromised.


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Contributors:
Original rule written by Max Vision <vision@whitehats.com>
Sourcefire Research Team
Judy Novak <judy.novak@sourcefire.com>

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Additional References:

Arachnids:
http://www.whitehats.com/info/IDS256

Miscellaneous:
http://biocserver.cwru.edu/~jose/shaft_analysis/


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