Ecosyste.ms: Advisories

Security Advisories: GSA_kwCzR0hTQS05N2MzLXc5Y3ItNnFjMs4AAqkN

Multiple vulnerabilities allow bypassing path filtering of agent-to-controller access control in Jenkins

The agent-to-controller security subsystem limits which files on the Jenkins controller can be accessed by agent processes.

Multiple vulnerabilities in the file path filtering implementation of Jenkins 2.318 and earlier, LTS 2.303.2 and earlier allow agent processes to read and write arbitrary files on the Jenkins controller file system, and obtain some information about Jenkins controller file systems.

SECURITY-2486 / CVE-2021-21690: Agent processes are able to completely bypass file path filtering by wrapping the file operation in an agent file path.

We expect that most of these vulnerabilities have been present since SECURITY-144 was addressed in the 2014-10-30 security advisory.

Jenkins 2.319, LTS 2.303.3 addresses these security vulnerabilities.

SECURITY-2486 / CVE-2021-21690: Agent processes are no longer able to completely bypass file path filtering by wrapping the file operation in an agent file path.

As some common operations are now newly subject to access control, it is expected that plugins sending commands from agents to the controller may start failing. Additionally, the newly introduced path canonicalization means that instances using a custom builds directory (Java system property jenkins.model.Jenkins.buildsDir) or partitioning JENKINS_HOME using symbolic links may fail access control checks. See the documentation for how to customize the configuration in case of problems.

If you are unable to immediately upgrade to Jenkins 2.319, LTS 2.303.3, you can install the Remoting Security Workaround Plugin. It will prevent all agent-to-controller file access using FilePath APIs. Because it is more restrictive than Jenkins 2.319, LTS 2.303.3, more plugins are incompatible with it. Make sure to read the plugin documentation before installing it.

Permalink: https://github.com/advisories/GHSA-97c3-w9cr-6qc2
JSON: https://advisories.ecosyste.ms/api/v1/advisories/GSA_kwCzR0hTQS05N2MzLXc5Y3ItNnFjMs4AAqkN
Source: GitHub Advisory Database
Origin: Unspecified
Severity: Critical
Classification: General
Published: almost 2 years ago
Updated: 4 months ago

CVSS Score: 9.1
CVSS vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H

Identifiers: GHSA-97c3-w9cr-6qc2, CVE-2021-21690
References:

• https://nvd.nist.gov/vuln/detail/CVE-2021-21690
• https://www.jenkins.io/security/advisory/2021-11-04/#SECURITY-2455
• https://github.com/jenkinsci/jenkins/commit/104c751d907919dd53f5090f84d53c671a66457b
• https://github.com/jenkinsci/jenkins/commit/5a245e42979abe4a26d41727c839521e36cedd74
• https://github.com/jenkinsci/jenkins/commit/63cde2daadc705edf086f2213b48c8c547f98358
• https://github.com/advisories/GHSA-97c3-w9cr-6qc2

Repository: https://github.com/jenkinsci/jenkins
Blast Radius: 1.0

Affected Packages