CVE-2020-17376

Public on

Last Modified: UTC

ImportantImportant ImpactWhat does this mean?
DescriptionStatementMitigationAdditional informationAffected PackagesCVSS Score DetailsWeakness (CWE)AcknowledgementsFAQ

Description

An information disclosure flaw was found in the live migration feature of OpenStack Nova. A user may gain access to destination host devices with the same path as those on the source host. This flaw allows an attacker to perform a soft reboot of an instance that has previously undergone live migration. The greatest impact of this vulnerability is to the confidentiality of many possible device types, but those at special risk are block storage devices, potentially revealing data of other users.

An information disclosure flaw was found in the live migration feature of OpenStack Nova. A user may gain access to destination host devices with the same path as those on the source host. This flaw allows an attacker to perform a soft reboot of an instance that has previously undergone live migration. The greatest impact of this vulnerability is to the confidentiality of many possible device types, but those at special risk are block storage devices, potentially revealing data of other users.

Statement

Red Hat OpenStack Platform 10 was initially marked as affected, however it has since been discovered that the flaw is actually not present in this version. For this reason, the update in RHSA-2020:3711 can be either applied or ignored for RHOSP 10.

Red Hat OpenStack Platform 10 was initially marked as affected, however it has since been discovered that the flaw is actually not present in this version. For this reason, the update in RHSA-2020:3711 can be either applied or ignored for RHOSP 10.

Mitigation

Public clouds using non-default configurations (allowing untrusted users to initiate live migrations) face significant additional risk. If it is not possible to immediately apply patches, a temporary policy change is recommended: disable soft reboots by setting wait_soft_reboot_seconds to zero. This effectively forces any soft reboots to instead be overridden as a hard reboot. Find more information in Nova's documentation https://docs.openstack.org/nova/ussuri/configuration/config.html

Deployments which use unique device paths for each cinder volume face an extremely low risk of being affected by this flaw.

Additional information

  • Bugzilla 1869426: openstack-nova: Soft reboot after live-migration reverts instance to original source domain XML
  • CWE-200: Exposure of Sensitive Information to an Unauthorized Actor
  • FAQ: Frequently asked questions about CVE-2020-17376

Common Vulnerability Scoring System (CVSS) Score Details

Important note

CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).

CVSS v3 Score Breakdown
Red HatNVD

CVSS v3 Base Score

8.3

8.3

Attack Vector

Network

Network

Attack Complexity

Low

Low

Privileges Required

Low

Low

User Interaction

None

None

Scope

Unchanged

Unchanged

Confidentiality Impact

High

High

Integrity Impact

High

High

Availability Impact

Low

Low

CVSS v3 Vector

Red Hat: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:L

NVD: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:L

Red Hat CVSS v3 Score Explanation

Availability is rated as low because the problem can only be triggered once per live-migration. While this could interrupt a service, it cannot bring it down indefinitely. OpenStack does not allow unauthenticated users to trigger soft reboots, so privileges required is rated Low.

Availability is rated as low because the problem can only be triggered once per live-migration. While this could interrupt a service, it cannot bring it down indefinitely.

OpenStack does not allow unauthenticated users to trigger soft reboots, so privileges required is rated Low.

Acknowledgements

This issue was discovered by Lee Yarwood (Red Hat) and Tadayoshi Hosoya (NEC).

Frequently Asked Questions

Why is Red Hat's CVSS v3 score or Impact different from other vendors?

For open source software shipped by multiple vendors, the CVSS base scores may vary for each vendor's version depending on the version they ship, how they ship it, the platform, and even how the software is compiled. This makes scoring of vulnerabilities difficult for third-party vulnerability databases such as NVD that only provide a single CVSS base score for each vulnerability. Red Hat scores reflect how a vulnerability affects our products specifically.

For more information, see https://access.redhat.com/solutions/762393.

My product is listed as "Under investigation" or "Affected", when will Red Hat release a fix for this vulnerability?

  • "Under investigation" doesn't necessarily mean that the product is affected by this vulnerability. It only means that our Analysis Team is still working on determining whether the product is affected and how it is affected.
  • "Affected" means that our Analysis Team has determined that this product is affected by this vulnerability and might release a fix to address this in the near future.

What can I do if my product is listed as "Will not fix"?

A "will not fix" status means that a fix for an affected product version is not planned or not possible due to complexity, which may create additional risk.

Available options depend mostly on the Impact of the vulnerability and the current Life Cycle phase of your product. Overall, you have the following options:
  • Upgrade to a supported product version that includes a fix for this vulnerability (recommended).
  • Apply a mitigation (if one exists).
  • Open a support case to request a prioritization of releasing a fix for this vulnerability.

What can I do if my product is listed as "Fix deferred"?

A deferred status means that a fix for an affected product version is not guaranteed due to higher-priority development work.

Available options depend mostly on the Impact of the vulnerability and the current Life Cycle phase of your product. Overall, you have the following options:
  • Apply a mitigation (if one exists).
  • Open a support case to request a prioritization of releasing a fix for this vulnerability.
  • Red Hat Engineering focuses on addressing high-priority issues based on their complexity or limited lifecycle support. Therefore, lower-priority issues will not receive immediate fixes.

What is a mitigation?

A mitigation is an action that can be taken to reduce the impact of a security vulnerability, without deploying any fixes.

I have a Red Hat product but it is not in the above list, is it affected?

The listed products were found to include one or more of the components that this vulnerability affects. These products underwent a thorough evaluation to determine their affectedness by this vulnerability. Note that layered products (such as container-based offerings) that consume affected components from any of the products listed in this table may be affected and are not represented.

Why is my security scanner reporting my product as vulnerable to this vulnerability even though my product version is fixed or not affected?

In order to maintain code stability and compatibility, Red Hat usually does not rebase packages to entirely new versions. Instead, we backport fixes and new features to an older version of the package we distribute. This can result in some security scanners that only consider the package version to report the package as vulnerable. To avoid this, we suggest that you use an approved vulnerability scanner from our Red Hat Vulnerability Scanner Certification program.

Want to get errata notifications? Sign up here.