#VU32481 Permissions, Privileges, and Access Controls in Xen - CVE-2014-7156

Vulnerability identifier: #VU32481

Vulnerability risk: Low

CVSSv4.0: 1.3 [CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2014-7156

CWE-ID: CWE-264

Exploitation vector: Local network

Exploit availability: No

Vulnerable software:
Xen
Server applications / Virtualization software

Vendor: Xen Project

Description

The vulnerability allows a remote non-authenticated attacker to perform service disruption.

The x86_emulate function in arch/x86/x86_emulate/x86_emulate.c in Xen 3.3.x through 4.4.x does not check the supervisor mode permissions for instructions that generate software interrupts, which allows local HVM guest users to cause a denial of service (guest crash) via unspecified vectors.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Xen: 3.3.0 - 3.3.2

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External links
https://lists.fedoraproject.org/pipermail/package-announce/2014-October/140418.html
https://lists.fedoraproject.org/pipermail/package-announce/2014-October/140483.html
https://lists.opensuse.org/opensuse-security-announce/2014-10/msg00002.html
https://lists.opensuse.org/opensuse-security-announce/2014-10/msg00003.html
https://secunia.com/advisories/61500
https://secunia.com/advisories/61858
https://secunia.com/advisories/61890
https://security.gentoo.org/glsa/glsa-201412-42.xml
https://support.citrix.com/article/CTX200218
https://www.debian.org/security/2014/dsa-3041
https://www.securityfocus.com/bid/70062
https://www.securitytracker.com/id/1030889
https://xenbits.xen.org/xsa/advisory-106.html

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the local network (LAN).

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.