Rule:

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Sid:
1832

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Summary:
This event is generated when activity relating to network chat clients is detected.

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Impact:
Policy Violation. Use of chat clients to communicate with unkown 
external sources may be against the policy of many organizations.

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Detailed Information:
Instant Messaging (IM) and other chat related client software can allow 
users to transfer files directly between hosts. This can allow malicious
users to circumvent the protection offered by a network firewall.

Vulnerabilities in these clients may also allow remote attackers to gain
unauthorized access to a host. This events indicates that an attempt has
been made to add a user to the contact list of Mirabilis' ICQ client via
a specially crafted URI on a website.

Certain versions of Mirabilis' ICQ client do not require user 
intervention before adding another ICQ user to the contact list. It is 
possible for a client to be added to the contact list via a specially 
crafted URI without the user's knowledge.

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Attack Scenarios:
An attacker might utilize this vulnerability in the ICQ client to gain 
access to a host, then upload a Trojan Horse program to gain control of 
that host.

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Ease of Attack:
Simple.

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False Positives:
None Known

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False Negatives:
None Known

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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
Brian Caswell <brian.caswell@sourcefire.com>
Nigel Houghton <nigel.houghton@sourcefire.com>

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Additional References:

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