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TITLE:
KVM Block Device Backend Security Bypass

SECUNIA ADVISORY ID:
SA29129

VERIFY ADVISORY:
http://secunia.com/advisories/29129/

CRITICAL:
Not critical

IMPACT:
Security Bypass

WHERE:
Local system

SOFTWARE:
KVM (Kernel-based Virtual Machine)
http://secunia.com/product/17812/

DESCRIPTION:
A vulnerability has been reported in KVM, which can be exploited by
malicious, local users to bypass certain security restrictions.

The vulnerability is caused due to the block device backends not
properly checking a guest's read or write attempts, which can be
exploited out of a KVM guest system to e.g. crash the KVM host or
potentially escape the virtualisation jail by writing into arbitrary
host memory.

Note: Successful exploitation requires privileges to send specially
crafted read or write requests to the block device  backends.

This is related to vulnerability #7 in:
SA25073

SOLUTION:
Restrict access to trusted users only.

PROVIDED AND/OR DISCOVERED BY:
Ian Jackson

ORIGINAL ADVISORY:
http://marc.info/?l=debian-security&m=120343592917055&w=2

OTHER REFERENCES:
SA25073:
http://secunia.com/advisories/25073/

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

Subscribe:
http://secunia.com/secunia_security_advisories/

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