XenSource Xen 4.2/4.3/4.4/4.5 QEMU/Xen Block Unplug Protocol access control

CVSS Meta Temp Score
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4.6$0-$5k0.00

A vulnerability classified as problematic has been found in XenSource Xen 4.2/4.3/4.4/4.5 (Virtualization Software). Affected is an unknown code of the component QEMU/Xen Block Unplug Protocol Handler. The manipulation with an unknown input leads to a access control vulnerability. CWE is classifying the issue as CWE-264. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

Use-after-free vulnerability in QEMU in Xen 4.5.x and earlier does not completely unplug emulated block devices, which allows local HVM guest users to gain privileges by unplugging a block device twice.

The weakness was presented 08/03/2015 by Donghai Zhu as XSA-139 as confirmed security advisory (Website). The advisory is available at xenbits.xen.org. This vulnerability is traded as CVE-2015-5166 since 07/01/2015. Local access is required to approach this attack. A authentication is needed for exploitation. The technical details are unknown and an exploit is not available. This vulnerability is assigned to T1068 by the MITRE ATT&CK project. The advisory points out:

When unplugging an emulated block device the device was not fully unplugged, meaning a second unplug attempt would attempt to unplug the device a second time using a previously freed pointer.

The vulnerability scanner Nessus provides a plugin with the ID 85480 (Fedora 22 : qemu-2.3.1-1.fc22 (2015-13402)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Fedora Local Security Checks. The commercial vulnerability scanner Qualys is able to test this issue with plugin 168231 (OpenSuSE Security Update for xen (openSUSE-SU-2015:2003-1)).

Applying the patch xsa139-qemuu-4.5.patch is able to eliminate this problem. The bugfix is ready for download at xenbits.xen.org. A possible mitigation has been published immediately after the disclosure of the vulnerability.

The vulnerability is also documented in the databases at X-Force (105253) and Tenable (85480). See 76323, 76879 and 77069 for similar entries.

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB CVSS-B Score: 🔍
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CVSSv3info

VulDB Meta Base Score: 5.3
VulDB Meta Temp Score: 4.6

VulDB Base Score: 5.3
VulDB Temp Score: 4.6
VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv2info

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Exploitinginfo

Class: Access control
CWE: CWE-264
ATT&CK: T1068

Local: Yes
Remote: No

Availability: 🔍
Status: Unproven

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Nessus ID: 85480
Nessus Name: Fedora 22 : qemu-2.3.1-1.fc22 (2015-13402)
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍

OpenVAS ID: 867773
OpenVAS Name: Fedora Update for xen FEDORA-2015-15946
OpenVAS File: 🔍
OpenVAS Family: 🔍

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Qualys Name: 🔍

Threat Intelligenceinfo

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Countermeasuresinfo

Recommended: Patch
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Patch: xsa139-qemuu-4.5.patch

Timelineinfo

07/01/2015 🔍
08/03/2015 +33 days 🔍
08/03/2015 +0 days 🔍
08/03/2015 +0 days 🔍
08/03/2015 +0 days 🔍
08/03/2015 +0 days 🔍
08/04/2015 +1 days 🔍
08/04/2015 +0 days 🔍
08/12/2015 +8 days 🔍
06/07/2022 +2491 days 🔍

Sourcesinfo

Vendor: citrix.com

Advisory: XSA-139
Researcher: Donghai Zhu
Status: Confirmed
Confirmation: 🔍

CVE: CVE-2015-5166 (🔍)
X-Force: 105253 - Xen block unplug protocol privilege escalation
SecurityTracker: 1033175 - Xen QEMU Block Unplug Protocol Use-After-Free Lets Local Users on a Guest System Gain Elevated Privileges on the Host System
Vulnerability Center: 51731 - Xen through 4.5.x Remote Code Execution due to Use-After-Free in QEMU Block Unplug Protocol, Medium
SecurityFocus: 76152 - Xen CVE-2015-5166 Local Privilege Escalation Vulnerability

See also: 🔍

Entryinfo

Created: 08/04/2015 10:51
Updated: 06/07/2022 10:12
Changes: 08/04/2015 10:51 (71), 09/10/2017 19:23 (14), 06/07/2022 10:12 (3)
Complete: 🔍

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