Rule:

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Sid:
3079

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Summary:
This event is generated when an attempt is made to exploit a buffer
overflow associated with Microsoft's processing of an animated cursor
file.

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Impact:
A successful attack may permit a buffer overflow that allows the execution
of arbitrary code at the privilege level of the user downloading the
malicious file.

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Detailed Information:
A vulnerability exists in the way the Microsoft Windows LoadImage API validates
animated cursor (ANI) files. An invalid length associated with a structure
supporting the properties of the animated cursor can cause a buffer overflow
and the subsequent execution of arbirary code in the context of the current user.

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Affected Systems:
	Windows 98, ME, NT, 2000, XP (not SP2), and Server 2003

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Attack Scenarios:
An attacker can entice a user to download a malicious animated cursor
file, causing a buffer overflow and the subsequent execution of arbitrary
code on the vulnerable client.

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Ease of Attack:
Simple.  Exploits exist.

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False Positives:
None known.

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False Negatives:
In order to avoid potential evasion techniques, http_inspect should be
configured with "flow_depth 0" so that all HTTP server response traffic is
inspected.

WARNING
Setting flow_depth 0 will cause performance problems in some situations.
WARNING

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Corrective Action:
Apply the patch(s) discussed in Microsoft bulletin MS05-002.

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

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Additional References

Microsoft Technet:
http://www.microsoft.com/technet/security/bulletin/MS05-002.mspx

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