Rule:

--
Sid:
247

--
Summary:
This event is generated when an mstream DDoS client communicates with a handler.

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

--
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.

--
Affected Systems:
Any mstream compromised host.

--
Attack Scenarios:
After a host becomes an mstream client, it will attempt to communicate with handlers. 

--
Ease of Attack:
Simple. mstream code is freely available.

--
False Positives:
None Known.

--
False Negatives:
There are other known client-to-handler ports in addition to 12754.

--
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.

--
Contributors:
Original rule writer unknown
Sourcefire Research Team
Judy Novak <judy.novak@sourcefire.com>

--
Additional References:

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

--
