542.txt

This is the snapshot of Snot Latest Rules

Rule:

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Sid:
542

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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 event indicates that an IRC nickname change has been made from a
client originating from the protected network to an IRC server external
to the protected network.

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Attack Scenarios:
A user may transfer sensitive company information to an external party
using the file transfer capabilities of an IM client.

An attacker might utilize a vulnerability in an IM 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 Vulnerability Research Team
Brian Caswell <[e-mail]>
Nigel Houghton <[e-mail]>

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Additional References:

IRC Protocol:
http://www.irchelp.org/irchelp/rfc/

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