Vulnerability identifier: #VU40617

Vulnerability risk: Low

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

CVE-ID: CVE-2015-7972

CWE-ID: CWE-399

Exploitation vector: 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 (1) libxl_set_memory_target function in tools/libxl/libxl.c and (2) libxl__build_post function in tools/libxl/libxl_dom.c in Xen 3.4.x through 4.6.x do not properly calculate the balloon size when using the populate-on-demand (PoD) system, which allows local HVM guest users to cause a denial of service (guest crash) via unspecified vectors related to "heavy memory pressure."

Mitigation
Install update from vendor's website.

Vulnerable software versions

Xen: 3.4.0 - 4.6.0

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External links
http://lists.fedoraproject.org/pipermail/package-announce/2015-November/171082.html
http://lists.fedoraproject.org/pipermail/package-announce/2015-November/171185.html
http://lists.fedoraproject.org/pipermail/package-announce/2015-November/171249.html
http://lists.opensuse.org/opensuse-updates/2015-11/msg00063.html
http://support.citrix.com/article/CTX202404
http://www.debian.org/security/2015/dsa-3414
http://www.securityfocus.com/bid/77365
http://www.securitytracker.com/id/1034036
http://xenbits.xen.org/xsa/advisory-153.html
http://security.gentoo.org/glsa/201604-03

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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 Internet.

Is there known malware, which exploits this vulnerability?

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