2452.txt

snort入侵检测规则文件2.4 Snort是众所周知的网络入侵检测工具

Rule:

--
Sid:
2452

--
Summary:
This event is generated when a host in your network that has Yahoo Instant Messenger running attempts to maintain contact with a Yahoo IM server.

--
Impact:
Possible policy violation.  Instant Messenger programs may not be appropriate in certain network environments.

--
Detailed Information:
Hosts running Yahoo IM periodically communicate with a Yahoo IM server to maintain their connection.  This is a keep-alive message that simply indicates the presences of a host running Yahoo IM.

--
Affected Systems:
Any host running Yahoo Instant Messenger.

--
Attack Scenarios:
This particular type of Yahoo IM exchange has no known attacks, however it may represent a policy violation because the host is running Yahoo IM.

--
Ease of Attack:
A host running Yahoo IM will automatically ping a Yahoo IM server.

--
False Positives:
None Known.

--
False Negatives:
It may be possible for Yahoo IM traffic to use other ports than the default expected ones.  

--
Corrective Action:
Disallow the use of IM clients on the protected network and enforce or implement an organization wide policy on the use of IM clients.

--
Contributors:
Sourcefire Research Team
Judy Novak <[e-mail]>
--
Additional References:
Yahoo Protocol
http://www.cse.iitb.ac.in/~varunk/YahooProtocol.htm

--