Rule

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Sid
15382

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Summary:
This event is generated when an attempt is made to exploit a known vulnerability in x_font_server.

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Impact:
Denial of Service. Information disclosure. Loss of integrity. 

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Detailed Information:
Integer overflow in the build_range function in X.Org X Font Server (xfs) before 1.0.5 allows context-dependent attackers to execute arbitrary code via (1) QueryXBitmaps and (2) QueryXExtents protocol requests with crafted size values, which triggers a heap-based buffer overflow.

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Affected Systems:
x.org x_font_server 1.0.1
x.org x_font_server 1.0.2
x.org x_font_server 1.0.4

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Attack Scenarios:
In an integer overflow attack, the attacker is able to control an integer value that can be made to be too large to store appropriately. The value may then wrap to become a small or negative value. At best this may cause a Denial of Service to occur, at worst this could lead to a buffer overflow which then allows the attacker to execute code on the system.

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Ease of Attack:
Medium.

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False Positives:
None known.

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False Negatives:
None known.

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Corrective Action:
Upgrade to the latest non-affected version of the software.

Apply the appropriate vendor supplied patches.

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Contributors:
Sourcefire Vulnerability Research Team
This document was generated from data supplied by the National Vulnerability Database. A product of the National Institute of Standards and Technology.
For more information see http://nvd.nist.gov/

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Additional References:

NIST CVE-2007-4568:
http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2007-4568
 
Common Weakness Enumeration:
http://cwe.mitre.org/data/definitions/190.html
 
Common Attack Pattern Enumeration and Classification:
http://capec.mitre.org/data/definitions/92.html

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