Rule:

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Sid:
1225

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Summary:
This event is generated when an attempt to exploit a weakness in the authentication mechanism used to connect to an X windows server is made.

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Impact:
Possible theft of data and control of the targeted machine leading to a compromise of all resources the machine is connected to.

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Detailed Information:
Implementations of the X windows system from the X consortium may use weak authentication methods when allowing remote machines to connect to a host running X windows.

XDM is used to allow remote users access to the remote X window server. When configured incorrectly, this may allow an unathorised user to connect to the display.

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Attack Scenarios:
The remote attacker may scan the host for listening X window servers, then connect to the remote host using XDM.

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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 connections to X servers from hosts outside the protected network.

Apply the appropriate vendor patches.

Upgrade to the latest version of the software.

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Contributors:
Original Rule Writer Max Vision <vision@whitehats.com>
Sourcefire Research Team
Nigel Houghton <nigel.houghton@sourcefire.com>

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Additional References:

CVE:
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-1999-0241

CIAC:
http://ciac.llnl.gov/ciac/bulletins/g-04.shtml

Whitehats arachNIDS
http://www.whitehats.com/info/IDS396

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