Rule:

--
Sid:
222

--
Summary:
This event is generated when ICMP traffic is sent between Tribe Flood Network 2000 (TFN2K) hosts.

--
Impact:
Attempted DDoS. It is possible there is a TFN2K host in your network. 

--
Detailed Information:
When TFN2K hosts communicate using ICMP, they may use an ICMP echo reply with an ICMP identification number of 0 and with a sequence of A's in the payload.  The tell-tale sequence of A's is a problem with the Base 64 encoding that was employed.   

--
Affected Systems:
Any TFN2K infected host. 

--
Attack Scenarios:
TFN2K hosts communicate with each other for various reasons for the ultimate purpose of attacking a target.

--
Ease of Attack:
Simple. TFN2K is freely available.

--
False Positives:
None Known.

--
False Negatives:
None Known.

--
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 written by Max Vision <vision@whitehats.com>
Sourcefire Research Team
Judy Novak <judy.novak@sourcefire.com>

--
Additional References:

Arachnids:
http://www.whitehats.com/info/IDS425

--
