#VU32214 Permissions, Privileges, and Access Controls in Xen - CVE-2016-9386

Vulnerability identifier: #VU32214

Vulnerability risk: Low

CVSSv4.0: 5.9 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2016-9386

CWE-ID: CWE-264

Exploitation vector: Local

Exploit availability: No

Vulnerable software:
Xen
Server applications / Virtualization software

Vendor: Xen Project

Description

The vulnerability allows a local authenticated user to execute arbitrary code.

The x86 emulator in Xen does not properly treat x86 NULL segments as unusable when accessing memory, which might allow local HVM guest users to gain privileges via vectors involving "unexpected" base/limit values.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Xen: 4.24

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External links
https://www.securityfocus.com/bid/94471
https://www.securitytracker.com/id/1037340
https://xenbits.xen.org/xsa/advisory-191.html
https://security.gentoo.org/glsa/201612-56
https://support.citrix.com/article/CTX218775

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Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

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