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TITLE:
Xen GDT/LDT Access Denial of Service Vulnerability

SECUNIA ADVISORY ID:
SA42395

VERIFY ADVISORY:
Secunia.com
http://secunia.com/advisories/42395/
Customer Area (Credentials Required)
https://ca.secunia.com/?page=viewadvisory&vuln_id=42395

RELEASE DATE:
2010-12-01

DISCUSS ADVISORY:
http://secunia.com/advisories/42395/#comments

AVAILABLE ON SITE AND IN CUSTOMER AREA:
 * Last Update
 * Popularity
 * Comments
 * Criticality Level
 * Impact
 * Where
 * Solution Status
 * Operating System / Software
 * CVE Reference(s)

http://secunia.com/advisories/42395/

ONLY AVAILABLE IN CUSTOMER AREA:
 * Authentication Level
 * Report Reliability
 * Secunia PoC
 * Secunia Analysis
 * Systems Affected
 * Approve Distribution
 * Remediation Status
 * Secunia CVSS Score
 * CVSS

https://ca.secunia.com/?page=viewadvisory&vuln_id=42395

ONLY AVAILABLE WITH SECUNIA CSI AND SECUNIA PSI:
 * AUTOMATED SCANNING

http://secunia.com/vulnerability_scanning/personal/
http://secunia.com/vulnerability_scanning/corporate/wsus_sccm_3rd_third_party_patching/

DESCRIPTION:
A vulnerability has been reported in Xen, which can be exploited by
malicious, local users to cause a DoS (Denial of Service).

The vulnerability is caused due to insufficient restriction checks
within the "fixup_page_fault()" function in xen/arch/x86/traps.c,
which can be exploited out of a guest system to trigger a "BUG_ON()"
by accessing the GDT/LDT mapping area directly.

Successful exploitation requires 64bit systems.

SOLUTION:
Restrict access to trusted users.

PROVIDED AND/OR DISCOVERED BY:
Reported by the vendor.

ORIGINAL ADVISORY:
http://lists.xensource.com/archives/html/xen-devel/2010-11/msg01650.html

OTHER REFERENCES:
Further details available in Customer Area:
http://secunia.com/products/corporate/EVM/

DEEP LINKS:
Further details available in Customer Area:
http://secunia.com/products/corporate/EVM/

EXTENDED DESCRIPTION:
Further details available in Customer Area:
http://secunia.com/products/corporate/EVM/

EXTENDED SOLUTION:
Further details available in Customer Area:
http://secunia.com/products/corporate/EVM/

EXPLOIT:
Further details available in Customer Area:
http://secunia.com/products/corporate/EVM/

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About:
This Advisory was delivered by Secunia as a free service to help
private users keeping their systems up to date against the latest
vulnerabilities.

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Definitions: (Criticality, Where etc.)
http://secunia.com/advisories/about_secunia_advisories/


Please Note:
Secunia recommends that you verify all advisories you receive by
clicking the link.
Secunia NEVER sends attached files with advisories.
Secunia does not advise people to install third party patches, only
use those supplied by the vendor.

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