CVE-2020-2121: Google kubernetes engine Remote Code Execution Vulnerability

HIGH
Advisory Identifier: GHSA-wf76-qgqq-gcfj
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CVSS 8.8
CWE-502
Published
Advisory Summary

CVE-2020-2121 is a HIGH (CVSS 8.8) remote code execution vulnerability (CWE-502: Deserialization of Untrusted Data) affecting Google kubernetes engine libraries in the Maven ecosystem. The issue involves rce vulnerability in google kubernetes engine plugin. Remediation is available by upgrading affected packages to version 0.8.1.

CVE-2020-2121 at a Glance

CVE Identifier CVE-2020-2121
GHSA Identifier GHSA-wf76-qgqq-gcfj
Severity HIGH
CVSS v3.1 Base Score 8.8
CWE Classification CWE-502: Deserialization of Untrusted Data
Affected Product Google kubernetes engine
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 8.8

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required Low (PR:L)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity High (I:H)
Availability High (A:H)

How to Fix CVE-2020-2121

To remediate this vulnerability, upgrade all affected Google kubernetes engine dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

org.jenkins-ci.plugins:google-kubernetes-engine fixed: 0.8.1 
<dependency>
    <groupId>org.jenkins-ci.plugins</groupId>
    <artifactId>google-kubernetes-engine</artifactId>
    <version>0.8.1</version>
</dependency>
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

mvn dependency:tree -Dincludes=org.jenkins-ci.plugins

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2020-2121, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree -Dincludes=org.jenkins-ci.plugins

Analyze the terminal output to locate any version of Google kubernetes engine in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.8.1), your application is affected.

Note: The mvn dependency:tree -Dincludes=org.jenkins-ci.plugins command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-502: Deserialization of Untrusted Data, where the product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid. In Google kubernetes engine, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

Google Kubernetes Engine Plugin 0.8.0 and earlier does not configure its YAML parser to prevent the instantiation of arbitrary types. This results in a remote code execution vulnerability exploitable by users able to provide YAML input files to Google Kubernetes Engine Plugin’s build step. Google Kubernetes Engine Plugin 0.8.1 configures its YAML parser to only instantiate safe types.

CVE-2020-2121 Affected Google kubernetes engine Versions

1 component(s)
Fixed Versions:
0.8.1
Product / Package Ecosystem Affected Versions Fixed Version
org.jenkins-ci.plugins:google-kubernetes-engine
maven/org.jenkins-ci.plugins/google-kubernetes-engine
Maven
< 0.8.1
0.8.1

References

NVD — CVE-2020-2121 NVD
https://nvd.nist.gov/vuln/detail/CVE-2020-2121
Google kubernetes engine Source Repository REPOSITORY
https://github.com/jenkinsci/google-kubernetes-engine-plugin
Google kubernetes engine Security Information SECURITY
https://jenkins.io/security/advisory/2020-02-12/#SECURITY-1731
Google kubernetes engine Security Information SECURITY
http://www.openwall.com/lists/oss-security/2020/02/12/3

Frequently Asked Questions

What is CVE-2020-2121?
CVE-2020-2121 is a security vulnerability in Google kubernetes engine involving RCE vulnerability in Google Kubernetes Engine Plugin under CWE-502: Deserialization of Untrusted Data.
Which Google kubernetes engine versions are affected?
Affected versions include releases prior to 0.8.1 across affected packages: org.jenkins-ci.plugins:google-kubernetes-engine.
What version fixes CVE-2020-2121?
Upgrading to 0.8.1 (or the latest patched release for your respective branch) resolves the vulnerability.
Is google-kubernetes-engine affected?
Yes, org.jenkins-ci.plugins:google-kubernetes-engine is affected in releases prior to 0.8.1. Upgrade your dependency to 0.8.1 or later.
What is the CVSS score of CVE-2020-2121?
CVE-2020-2121 has a CVSS v3.1 base score of 8.8 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2020-2121?
CVE-2020-2121 is classified under CWE-502: Deserialization of Untrusted Data (The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.).
How can I check Maven dependencies for CVE-2020-2121?
Run the dependency tree command: 'mvn dependency:tree -Dincludes=org.jenkins-ci.plugins'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-wf76-qgqq-gcfj",
  "modified" : "2023-01-14T05:27:29Z",
  "published" : "2022-05-24T17:08:47Z",
  "aliases" : [ "CVE-2020-2121" ],
  "summary" : "RCE vulnerability in Google Kubernetes Engine Plugin",
  "details" : "Google Kubernetes Engine Plugin 0.8.0 and earlier does not configure its YAML parser to prevent the instantiation of arbitrary types. This results in a remote code execution vulnerability exploitable by users able to provide YAML input files to Google Kubernetes Engine Plugin’s build step.\n\nGoogle Kubernetes Engine Plugin 0.8.1 configures its YAML parser to only instantiate safe types.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.jenkins-ci.plugins:google-kubernetes-engine"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.8.1"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2020-2121"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/jenkinsci/google-kubernetes-engine-plugin"
  }, {
    "type" : "WEB",
    "url" : "https://jenkins.io/security/advisory/2020-02-12/#SECURITY-1731"
  }, {
    "type" : "WEB",
    "url" : "http://www.openwall.com/lists/oss-security/2020/02/12/3"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-502" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2023-01-14T05:27:29Z",
    "nvd_published_at" : "2020-02-12T15:15:00Z"
  }
}