CVE-2019-3876

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Moderate Moderate Impact What does this mean?
5 CVSS v3 Base Score

Description

A flaw was found in the /oauth/token/request custom endpoint of the OpenShift OAuth server allowing for XSS generation of CLI tokens due to missing X-Frame-Options and CSRF protections. If not otherwise prevented, a separate XSS vulnerability via JavaScript could further allow for the extraction of these tokens.

Statement

This issue affects the OAuth server shipped in OpenShift Container Platform version v3.0 through v3.11. Red Hat Product Security has rated this issue as having a security impact of Moderate.

For additional information, refer to the Issue Severity Classification: https://access.redhat.com/security/updates/classification/.

Mitigation

Since at least v3.4, the OpenShift documentation [1] has specified the format for corsAllowedOrigins to accurately match intended hostnames. Since at least v3.7, installs will default to use the correct regular expression formatted variables. Earlier versions may be configured with plain strings, a configuration which will persist across cluster upgrades, opening them to cross origin vulnerabilities such as this.

At a minimum, you should ensure that the corsAllowedOrigin definition within master-config.yaml contains elements in the form 

corsAllowedOrigins:
- (?i)//my\.subdomain\.domain\.com(:|\z)

and not the form

corsAllowedOrigins:
- domain.com

as the first will permit cross origin requests only if the host matches exactly, whereas the second will permit from any host that merely contains the string (such as ABCDdomain.com or even domain.comABCD.com).

Footnotes:

[1] https://docs.openshift.com/container-platform/3.4/architecture/infrastructure_components/web_console.html#corsAllowedOrigins

Additional Information

External References

Content from www.cve.org is not included.https://www.cve.org/CVERecord?id=CVE-2019-3876

Content from nvd.nist.gov is not included.https://nvd.nist.gov/vuln/detail/CVE-2019-3876

Affected Packages and Issued Red Hat Security Errata

Products / Services Components State Errata
Red Hat OpenShift Container Platform 3.10 atomic-openshift Fix deferred
Red Hat OpenShift Container Platform 3.11 atomic-openshift Fixed RHSA-2019:1851
Red Hat OpenShift Container Platform 3.11 jenkins-2-plugins Fixed RHSA-2019:1851
Red Hat OpenShift Container Platform 3.4 atomic-openshift Out of support scope
Red Hat OpenShift Container Platform 3.5 atomic-openshift Out of support scope
Red Hat OpenShift Container Platform 3.6 atomic-openshift Out of support scope
Red Hat OpenShift Container Platform 3.7 atomic-openshift Out of support scope
Red Hat OpenShift Container Platform 3.9 atomic-openshift Fix deferred
Red Hat OpenShift Container Platform 4 openshift Not affected
Unless explicitly stated as not affected, all previous versions of packages in any minor update stream of a product listed here should be assumed vulnerable, although may not have been subject to full analysis.

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 Authorities (CNA) source for its products and services (see Red Hat classifications ).

CVSS v3 Score Breakdown Red Hat NVD
CVSS v3 Base Score 5 6.3
Attack Vector Network Network
Attack Complexity High Low
Privileges Required None None
User Interaction Required Required
Scope Unchanged Unchanged
Confidentiality Impact Low Low
Integrity Impact Low Low
Availability Impact Low Low

CVSS v3 Vector

Red Hat CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:L

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

Acknowledgements

This issue was discovered by Mo Khan (Red Hat).

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 This content is not included.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 This content is not included.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 This content is not included.Red Hat Vulnerability Scanner Certification program.

My product is listed as "Out of Support Scope". What does this mean?

 When a product is listed as "Out of Support Scope", it means a vulnerability with the impact level assigned to this CVE is no longer covered by its current support lifecycle phase. The product has been identified to contain the impacted component, but analysis to determine whether it is affected or not by this vulnerability was not performed. The product should be assumed to be affected. Customers are advised to apply any mitigation options documented on this page, consider removing or disabling the impacted component, or upgrade to a supported version of the product that has an update available.