Rule:
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Sid:
248

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Summary:
This event is generated when an mstream DDoS handler responds to an mstream client.

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Impact:
Severe.  If the list 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 client.

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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. At the highest level, clients communicate with handlers to inform them to launch attacks.  A client may communicate with a handler using a TCP packet to destination port 12754 with a string of ">" in the payload.  A handler responds to this with a TCP source port of 12754 and a string of ">" in the payload.

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Affected Systems:
Any mstream compromised host.

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Attack Scenarios:
An mstream handler may be respond to a communication from an mstream client.
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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 client-to-handler ports in addition to 12754.

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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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