Xen up to 4.11.x DEBUGCTL MSR access control

CVSS Meta Temp Score
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CTI Interest Score
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5.7$0-$5k0.00

Summaryinfo

A vulnerability has been found in Xen up to 4.11.x and classified as critical. Impacted is an unknown function of the component DEBUGCTL MSR. This manipulation causes access control. This vulnerability is tracked as CVE-2018-15468. The attack is restricted to local execution. No exploit exists. It is recommended to apply a patch to fix this issue.

Detailsinfo

A vulnerability has been found in Xen up to 4.11.x (Virtualization Software) and classified as critical. Affected by this vulnerability is an unknown part of the component DEBUGCTL MSR. The manipulation with an unknown input leads to a access control vulnerability. The CWE definition for the vulnerability is CWE-264. As an impact it is known to affect availability. The summary by CVE is:

An issue was discovered in Xen through 4.11.x. The DEBUGCTL MSR contains several debugging features, some of which virtualise cleanly, but some do not. In particular, Branch Trace Store is not virtualised by the processor, and software has to be careful to configure it suitably not to lock up the core. As a result, it must only be available to fully trusted guests. Unfortunately, in the case that vPMU is disabled, all value checking was skipped, allowing the guest to choose any MSR_DEBUGCTL setting it likes. A malicious or buggy guest administrator (on Intel x86 HVM or PVH) can lock up the entire host, causing a Denial of Service.

The bug was discovered 08/14/2018. The weakness was disclosed 08/17/2018 by Matthew Daley (Website). It is possible to read the advisory at xenbits.xen.org. This vulnerability is known as CVE-2018-15468 since 08/17/2018. Attacking locally is a requirement. The exploitation doesn't need any form of authentication. The technical details are unknown and an exploit is not publicly available. The attack technique deployed by this issue is T1068 according to MITRE ATT&CK.

The vulnerability scanner Nessus provides a plugin with the ID 112157 (Xen Project MSR_DEBUGCTL 'Branch Trace Store' DoS (XSA-269)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Misc. and running in the context l. The commercial vulnerability scanner Qualys is able to test this issue with plugin 171690 (SUSE Enterprise Linux Security Update for xen (SUSE-SU-2018:3490-1)).

Applying a patch is able to eliminate this problem. A possible mitigation has been published even before and not after the disclosure of the vulnerability.

The vulnerability is also documented in the databases at Tenable (112157) and SecurityFocus (BID 106182†). The entries VDB-107985, VDB-122910, VDB-123008 and VDB-123009 are pretty similar. Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.0
VulDB Meta Temp Score: 5.8

VulDB Base Score: 6.0
VulDB Temp Score: 5.7
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 6.0
NVD Vector: 🔍

CVSSv2info

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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
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NVD Base Score: 🔍

Exploitinginfo

Class: Access control
CWE: CWE-264
CAPEC: 🔍
ATT&CK: 🔍

Physical: Partially
Local: Yes
Remote: No

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Nessus ID: 112157
Nessus Name: Xen Project MSR_DEBUGCTL 'Branch Trace Store' DoS (XSA-269)
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Context: 🔍

Qualys ID: 🔍
Qualys Name: 🔍

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Patch
Status: 🔍

0-Day Time: 🔍

Timelineinfo

08/14/2018 🔍
08/14/2018 +0 days 🔍
08/17/2018 +2 days 🔍
08/17/2018 +0 days 🔍
08/17/2018 +0 days 🔍
08/18/2018 +1 days 🔍
08/28/2018 +10 days 🔍
12/07/2018 +101 days 🔍
03/16/2020 +465 days 🔍

Sourcesinfo

Advisory: xenbits.xen.org
Researcher: Matthew Daley
Status: Confirmed

CVE: CVE-2018-15468 (🔍)
GCVE (CVE): GCVE-0-2018-15468
GCVE (VulDB): GCVE-100-123007
SecurityFocus: 106182 - Xen Multiple Privilege Escalation and Denial of Service Vulnerabilities

See also: 🔍

Entryinfo

Created: 08/18/2018 10:55
Updated: 03/16/2020 14:53
Changes: 08/18/2018 10:55 (71), 03/16/2020 14:53 (6)
Complete: 🔍
Cache ID: 216:F73:103

Be aware that VulDB is the high quality source for vulnerability data.

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