CVE-2020-2146: Mac Missing SSH Host Key Validation Vulnerability

MODERATE
Advisory Identifier: GHSA-rv9g-67f7-grq7
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CVSS 6.8
CWE-347
Published
Advisory Summary

CVE-2020-2146 is a MODERATE (CVSS 6.8) missing ssh host key validation vulnerability (CWE-347: Improper Verification of Cryptographic Signature) affecting Mac libraries in the Maven ecosystem. The issue involves missing ssh host key validation in mac plugin. Remediation is available by upgrading affected packages to version 1.2.0.

CVE-2020-2146 at a Glance

CVE Identifier CVE-2020-2146
GHSA Identifier GHSA-rv9g-67f7-grq7
Severity MODERATE
CVSS v3.1 Base Score 6.8
CWE Classification CWE-347: Improper Verification of Cryptographic Signature
Affected Product Mac
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 6.8

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

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

How to Fix CVE-2020-2146

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

fr.edf.jenkins.plugins:mac fixed: 1.2.0 
<dependency>
    <groupId>fr.edf.jenkins.plugins</groupId>
    <artifactId>mac</artifactId>
    <version>1.2.0</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=fr.edf.jenkins.plugins

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2020-2146, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree -Dincludes=fr.edf.jenkins.plugins

Analyze the terminal output to locate any version of Mac in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.2.0), your application is affected.

Note: The mvn dependency:tree -Dincludes=fr.edf.jenkins.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-347: Improper Verification of Cryptographic Signature, where the product does not verify, or incorrectly verifies, the cryptographic signature for data. In Mac, 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

Mac Plugin 1.1.0 and earlier does not use SSH host key validation when connecting to Mac Cloud host launched by the plugin. This lack of validation could be abused using a man-in-the-middle attack to intercept these connections to build agents. Mac Plugin 1.2.0 validates SSH host keys when connecting to agents.

CVE-2020-2146 Affected Mac Versions

1 component(s)
Fixed Versions:
1.2.0
Product / Package Ecosystem Affected Versions Fixed Version
fr.edf.jenkins.plugins:mac
maven/fr.edf.jenkins.plugins/mac
Maven
< 1.2.0
1.2.0

References

NVD — CVE-2020-2146 NVD
https://nvd.nist.gov/vuln/detail/CVE-2020-2146
Security Fix Commit FIX COMMIT
https://github.com/jenkinsci/mac-plugin/commit/ba1a8206c7ef990d37498e5abdf210990ef046b5
Mac Source Repository REPOSITORY
https://github.com/jenkinsci/mac-plugin
Mac Security Information SECURITY
https://jenkins.io/security/advisory/2020-03-09/#SECURITY-1692
Mac Security Information SECURITY
http://www.openwall.com/lists/oss-security/2020/03/09/1

Frequently Asked Questions

What is CVE-2020-2146?
CVE-2020-2146 is a security vulnerability in Mac involving Missing SSH host key validation in Mac Plugin under CWE-347: Improper Verification of Cryptographic Signature.
Which Mac versions are affected?
Affected versions include releases prior to 1.2.0 across affected packages: fr.edf.jenkins.plugins:mac.
What version fixes CVE-2020-2146?
Upgrading to 1.2.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is mac affected?
Yes, fr.edf.jenkins.plugins:mac is affected in releases prior to 1.2.0. Upgrade your dependency to 1.2.0 or later.
What is the CVSS score of CVE-2020-2146?
CVE-2020-2146 has a CVSS v3.1 base score of 6.8 (MODERATE) with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N.
What CWE is associated with CVE-2020-2146?
CVE-2020-2146 is classified under CWE-347: Improper Verification of Cryptographic Signature (The product does not verify, or incorrectly verifies, the cryptographic signature for data.).
How can I check Maven dependencies for CVE-2020-2146?
Run the dependency tree command: 'mvn dependency:tree -Dincludes=fr.edf.jenkins.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-rv9g-67f7-grq7",
  "modified" : "2023-01-14T05:24:25Z",
  "published" : "2022-05-24T17:10:29Z",
  "aliases" : [ "CVE-2020-2146" ],
  "summary" : "Missing SSH host key validation in Mac Plugin",
  "details" : "Mac Plugin 1.1.0 and earlier does not use SSH host key validation when connecting to Mac Cloud host launched by the plugin. This lack of validation could be abused using a man-in-the-middle attack to intercept these connections to build agents.\n\nMac Plugin 1.2.0 validates SSH host keys when connecting to agents.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "fr.edf.jenkins.plugins:mac"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.2.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2020-2146"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/jenkinsci/mac-plugin/commit/ba1a8206c7ef990d37498e5abdf210990ef046b5"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/jenkinsci/mac-plugin"
  }, {
    "type" : "WEB",
    "url" : "https://jenkins.io/security/advisory/2020-03-09/#SECURITY-1692"
  }, {
    "type" : "WEB",
    "url" : "http://www.openwall.com/lists/oss-security/2020/03/09/1"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-347" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2023-01-14T05:24:25Z",
    "nvd_published_at" : "2020-03-09T16:15:00Z"
  }
}