Rule:
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Sid:
244

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Summary:
This event is generated when a DDoS mstream handler directs an mstream agent to begin an attack against a specified target. 

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Impactn:
Severe. If the listed source IP is in your network, it may be an mstream handler.  If the listed destination IP is in your network, it may be an mstream agent.

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Detailed Information:
The mstream DDoS uses a tiered structure of compromised hosts to coordinate and participate in a distributed denial of service attack.  There are "handler" hosts that are used to coordinate the attacks and "agent" hosts that launch the attack.  A handler can direct a particular agent to attack a target. It directs the agent by sending it a UDP packet to destination port 10498 with a string of "stream/" in the payload.  The target IP and duration of the attack will also be included in the payload.

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Affected Systems:
Any mstream compromised host.

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Attack Scenarios:
After a host becomes an mstream agent, it will likely be directed to participate in a DDoS attack.
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Ease of Attack:
Simple. mstream code is freely available.

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False Positives:
None Known.

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False Negatives:
There are other known handler-to-agent ports in addition to 10498.

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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 writer unknown
Sourcefire Research Team
Judy Novak <judy.novak@sourcefire.com>

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Additional References:

CVE:
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2000-0138

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