XenSource Xen 4.2/4.3/4.4/4.5 compat_iret resource management

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A vulnerability was found in XenSource Xen 4.2/4.3/4.4/4.5 (Virtualization Software). It has been declared as problematic. Affected by this vulnerability is the function compat_iret. The manipulation with an unknown input leads to a resource management vulnerability. The CWE definition for the vulnerability is CWE-399. As an impact it is known to affect availability. The summary by CVE is:

The compat_iret function in Xen 3.1 through 4.5 iterates the wrong way through a loop, which allows local 32-bit PV guest administrators to cause a denial of service (large loop and system hang) via a hypercall_iret call with EFLAGS.VM set.

The weakness was shared 06/11/2015 by Andrew Cooper with Citrix as XSA-136 as confirmed security advisory (Website). It is possible to read the advisory at xenbits.xen.org. This vulnerability is known as CVE-2015-4164 since 06/02/2015. The exploitation appears to be easy. Attacking locally is a requirement. The exploitation doesn't need any form of authentication. Technical details of the vulnerability are known, but there is no available exploit.

The vulnerability scanner Nessus provides a plugin with the ID 84169 (Debian DSA-3286-1 : xen - security update), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Debian Local Security Checks. The commercial vulnerability scanner Qualys is able to test this issue with plugin 370035 (Citrix XenServer Security Update (CTX201145)).

Applying a patch is able to eliminate this problem. A possible mitigation has been published immediately after the disclosure of the vulnerability.

The vulnerability is also documented in the databases at X-Force (103788), Tenable (84169), SecurityFocus (BID 75149†), SecurityTracker (ID 1032569†) and Vulnerability Center (SBV-50588†).







CPE 2.3info

CPE 2.2info


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VulDB Meta Base Score: 4.0
VulDB Meta Temp Score: 3.5

VulDB Base Score: 4.0
VulDB Temp Score: 3.5
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Class: Resource management
CWE: CWE-399 / CWE-404

Local: Yes
Remote: No

Availability: 🔍
Status: Unproven

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Nessus ID: 84169
Nessus Name: Debian DSA-3286-1 : xen - security update
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OpenVAS ID: 703286
OpenVAS Name: Debian Security Advisory DSA 3286-1 (xen - security update)
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Threat Intelligenceinfo

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Recommended: Patch
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06/02/2015 🔍
06/11/2015 +9 days 🔍
06/11/2015 +0 days 🔍
06/11/2015 +0 days 🔍
06/12/2015 +1 days 🔍
06/12/2015 +0 days 🔍
06/15/2015 +3 days 🔍
06/15/2015 +0 days 🔍
06/16/2015 +1 days 🔍
05/21/2022 +2531 days 🔍


Vendor: citrix.com

Advisory: XSA-136
Researcher: Andrew Cooper
Organization: Citrix
Status: Confirmed
Confirmation: 🔍

CVE: CVE-2015-4164 (🔍)

X-Force: 103788 - Xen compat_iret() function denial of service
SecurityFocus: 75149 - Xen CVE-2015-4164 Local Denial of Service Vulnerability
SecurityTracker: 1032569 - Xen Logic Error in compat_iret() Lets Local Guest Users Deny Service on the Host System
Vulnerability Center: 50588 - Xen 3.1 through 4.5 Local DoS via a Hypercall_iret Call with EFLAGS.VM Set, Medium


Created: 06/12/2015 11:11 AM
Updated: 05/21/2022 02:17 AM
Changes: 06/12/2015 11:11 AM (78), 10/09/2017 09:49 AM (6), 05/21/2022 02:17 AM (3)
Complete: 🔍
Cache ID: 3:0FA:40


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