Rule:
alert tcp $HOME_NET any -> $EXTERNAL_NET 5100 (msg: "CHAT Yahoo IM webcam request"; flow:to_server, established; content:"|3c 52|"; offset: 0; depth:2; pcre:"/^\x3c(REQIMG|RVWCFG)\x3e/ism"; classtype:policy-violation; sid:2460; rev:1;)

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Sid:
2460

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Summary:
This event is generated when a host in your network that has Yahoo Instant Messenger running requests to view a webcam of another Yahoo IM user. 

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

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Detailed Information:
This event indicates that a Yahoo IM user in your network is requesting to view a webcam of another Yahoo IM user.  While there are no known exploits associated with showing or viewing webcams, it is possible that this activity is inappropriate in certain environments.

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Affected Systems:
Any host running Yahoo Instant Messenger.

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Attack Scenarios:
No know attack scenarios.

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Ease of Attack:
No know attack scenarios.

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False Positives:
None Known.

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

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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.

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Contributors:
Sourcefire Research Team
Judy Novak <judy.novak@sourcefire.com>
