Permissions, Privileges, and Access Controls in Xen

1) Permissions, Privileges, and Access Controls

EUVDB-ID: #VU32481

Risk: Low

CVSSv3.1: 3.8 [CVSS:3.1/CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/E:U/RL:O/RC:C]

CVE-ID: CVE-2014-7156

CWE-ID: CWE-264 - Permissions, Privileges, and Access Controls

Exploit availability: No

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

External links

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

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.