Xen 4.5.x/4.6.x/4.7.x Privilege Check calculation

CVSS Meta Temp Score
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CTI Interest Score
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5.3$0-$5k0.00

Summaryinfo

A vulnerability described as problematic has been identified in Xen 4.5.x/4.6.x/4.7.x. This issue affects some unknown processing of the component Privilege Check. Such manipulation leads to calculation. This vulnerability is uniquely identified as CVE-2016-9377. Local access is required to approach this attack. No exploit exists. It is advisable to implement a patch to correct this issue.

Detailsinfo

A vulnerability was found in Xen 4.5.x/4.6.x/4.7.x (Virtualization Software) and classified as problematic. Affected by this issue is an unknown code block of the component Privilege Check. The manipulation with an unknown input leads to a calculation vulnerability. Using CWE to declare the problem leads to CWE-682. The product performs a calculation that generates incorrect or unintended results that are later used in security-critical decisions or resource management. Impacted is availability. CVE summarizes:

Xen 4.5.x through 4.7.x on AMD systems without the NRip feature, when emulating instructions that generate software interrupts, allows local HVM guest OS users to cause a denial of service (guest crash) by leveraging IDT entry miscalculation.

The bug was discovered 11/22/2016. The weakness was disclosed 11/22/2016 by Andrew Cooper with Citrix as XSA-196 as confirmed security advisory (Website). The advisory is shared for download at xenbits.xen.org. The public release has been coordinated in cooperation with the vendor. This vulnerability is handled as CVE-2016-9377 since 11/17/2016. The exploitation is known to be easy. The attack may be launched remotely. The requirement for exploitation is a simple authentication. There are neither technical details nor an exploit publicly available.

The vulnerability scanner Nessus provides a plugin with the ID 95493 (Fedora 25 : xen (2016-999e1a6927)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Fedora Local Security Checks and running in the context l. The commercial vulnerability scanner Qualys is able to test this issue with plugin 276244 (Fedora Security Update for xen (FEDORA-2016-999e1a6927)).

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 Tenable (95493), SecurityFocus (BID 94475†) and SecurityTracker (ID 1037345†). The entries VDB-93805, VDB-93806, VDB-93807 and VDB-93808 are pretty similar. Once again VulDB remains the best source for vulnerability data.

Productinfo

Type

Name

Version

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.5
VulDB Meta Temp Score: 5.4

VulDB Base Score: 5.5
VulDB Temp Score: 5.3
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 5.5
NVD Vector: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

NVD Base Score: 🔍

Exploitinginfo

Class: Calculation
CWE: CWE-682
CAPEC: 🔍
ATT&CK: 🔍

Physical: Partially
Local: Yes
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Nessus ID: 95493
Nessus Name: Fedora 25 : xen (2016-999e1a6927)
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Context: 🔍

OpenVAS ID: 58605
OpenVAS Name: Fedora Update for xen FEDORA-2016-999e1a6927
OpenVAS File: 🔍
OpenVAS Family: 🔍

Qualys ID: 🔍
Qualys Name: 🔍

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Patch
Status: 🔍

Reaction Time: 🔍
0-Day Time: 🔍
Exposure Time: 🔍

Timelineinfo

11/17/2016 🔍
11/22/2016 +5 days 🔍
11/22/2016 +0 days 🔍
11/22/2016 +0 days 🔍
11/22/2016 +0 days 🔍
11/25/2016 +3 days 🔍
11/25/2016 +0 days 🔍
12/05/2016 +10 days 🔍
02/22/2017 +79 days 🔍
06/10/2019 +838 days 🔍

Sourcesinfo

Advisory: XSA-196
Researcher: Andrew Cooper
Organization: Citrix
Status: Confirmed
Confirmation: 🔍
Coordinated: 🔍

CVE: CVE-2016-9377 (🔍)
GCVE (CVE): GCVE-0-2016-9377
GCVE (VulDB): GCVE-100-93812
SecurityFocus: 94475 - Xen Multiple Denial of Service Vulnerabilities
SecurityTracker: 1037345

See also: 🔍

Entryinfo

Created: 11/25/2016 12:01
Updated: 06/10/2019 06:59
Changes: 11/25/2016 12:01 (73), 06/10/2019 06:59 (13)
Complete: 🔍
Cache ID: 216::103

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