CVE-2023-23939: Azure/setup-kubectl Escalation Of Privilege Vulnerability For Vulnerability

LOW
Advisory Identifier: GHSA-p756-rfxh-x63h
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CVSS 3.0
CWE-732
Published
Advisory Summary

CVE-2023-23939 is a LOW (CVSS 3.0) escalation of privilege vulnerability for vulnerability (CWE-732: Incorrect Permission Assignment for Critical Resource) affecting Azure/setup-kubectl libraries in the GitHub Actions ecosystem. The issue involves escalation of privilege vulnerability for v3 and lower. Remediation is available by upgrading affected packages to version 3.

CVE-2023-23939 at a Glance

CVE Identifier CVE-2023-23939
GHSA Identifier GHSA-p756-rfxh-x63h
Severity LOW
CVSS v3.1 Base Score 3.0
CWE Classification CWE-732: Incorrect Permission Assignment for Critical Resource
Affected Product Azure/setup-kubectl
Package Ecosystem GitHub Actions
Published Date
Last Updated

Security Impact

CVSS: 3.0

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

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

How to Fix CVE-2023-23939

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

Azure/setup-kubectl fixed: 3 
Upgrade Azure/setup-kubectl to 3
Verify Direct and Transitive Dependencies

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

inspect dependencies for Azure/setup-kubectl

How to Check if You Are Affected

To determine whether your application is affected by CVE-2023-23939, inspect your project dependencies for Azure/setup-kubectl:

inspect dependencies for Azure/setup-kubectl

Analyze the terminal output to locate any version of Azure/setup-kubectl in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 3), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-732: Incorrect Permission Assignment for Critical Resource, where the product specifies permissions for a security-critical resource in a way that allows that resource to be read or modified by unintended actors. In Azure/setup-kubectl, 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

### Impact This vulnerability only impacts versions `v2` and lower. An insecure temporary creation of a file allows other actors on the Actions runner to replace the Kubectl binary created by this action because it is world writable. This Kubectl tool installer runs `fs.chmodSync(kubectlPath, 777)` to set permissions on the Kubectl binary, however, this allows any local user to replace the Kubectl binary. This allows privilege escalation to the user that can also run kubectl, most likely root. This attack is only possible if an attacker somehow breached the GitHub actions runner or if a user is utilizing an Action that maliciously executes this attack. No impacted customers have been reported. ### Patches This has been fixed and released in all versions `v3` and later. 755 permissions are used instead. ### Workarounds If users absolutely cannot upgrade to `v3` or higher than they should be extra diligent of the other GitHub actions they are using in a workflow and ensure that their GitHub actions runner is secure.

CVE-2023-23939 Affected Azure/setup-kubectl Versions

1 component(s)
Fixed Versions:
3
Product / Package Ecosystem Affected Versions Fixed Version
Azure/setup-kubectl
 GitHub Actions
< 3
3

References

GitHub Advisory / Wiki ADVISORY
https://github.com/Azure/setup-kubectl/security/advisories/GHSA-p756-rfxh-x63h
NVD — CVE-2023-23939 NVD
https://nvd.nist.gov/vuln/detail/CVE-2023-23939
Security Fix Commit FIX COMMIT
https://github.com/Azure/setup-kubectl/commit/d449d75495d2b9d1463555bb00ca3dca77a42ab6
Azure/setup-kubectl Source Repository REPOSITORY
https://github.com/Azure/setup-kubectl

Frequently Asked Questions

What is CVE-2023-23939?
CVE-2023-23939 is a security vulnerability in Azure/setup-kubectl involving Escalation of privilege vulnerability for v3 and lower under CWE-732: Incorrect Permission Assignment for Critical Resource.
Which Azure/setup-kubectl versions are affected?
Affected versions include releases prior to 3 across affected packages: Azure/setup-kubectl.
What version fixes CVE-2023-23939?
Upgrading to 3 (or the latest patched release for your respective branch) resolves the vulnerability.
Is Azure/setup-kubectl affected?
Yes, Azure/setup-kubectl is affected in releases prior to 3. Upgrade your dependency to 3 or later.
What is the CVSS score of CVE-2023-23939?
CVE-2023-23939 has a CVSS v3.1 base score of 3.0 (LOW) with vector string CVSS:3.1/AV:A/AC:H/PR:L/UI:N/S:C/C:N/I:L/A:N.
What CWE is associated with CVE-2023-23939?
CVE-2023-23939 is classified under CWE-732: Incorrect Permission Assignment for Critical Resource (The product specifies permissions for a security-critical resource in a way that allows that resource to be read or modified by unintended actors.).
How can I check GitHub Actions dependencies for CVE-2023-23939?
Run the dependency tree command: 'inspect dependencies for Azure/setup-kubectl'. 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-p756-rfxh-x63h",
  "modified" : "2023-03-07T20:07:27Z",
  "published" : "2023-03-07T20:07:27Z",
  "aliases" : [ "CVE-2023-23939" ],
  "summary" : "Azure/setup-kubectl: Escalation of privilege vulnerability for v3 and lower",
  "details" : "### Impact\n\nThis vulnerability only impacts versions `v2` and lower. An insecure temporary creation of a file allows other actors on the Actions runner to replace the Kubectl binary created by this action because it is world writable. This Kubectl tool installer runs `fs.chmodSync(kubectlPath, 777)` to set permissions on the Kubectl binary, however, this allows any local user to replace the Kubectl binary. This allows privilege escalation to the user that can also run kubectl, most likely root. This attack is only possible if an attacker somehow breached the GitHub actions runner or if a user is utilizing an Action that maliciously executes this attack.\n\nNo impacted customers have been reported.\n\n### Patches\n\nThis has been fixed and released in all versions `v3` and later. 755 permissions are used instead.\n\n### Workarounds\n\nIf users absolutely cannot upgrade to `v3` or higher than they should be extra diligent of the other GitHub actions they are using in a workflow and ensure that their GitHub actions runner is secure.\n",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:A/AC:H/PR:L/UI:N/S:C/C:N/I:L/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "GitHub Actions",
      "name" : "Azure/setup-kubectl"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "3"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/Azure/setup-kubectl/security/advisories/GHSA-p756-rfxh-x63h"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2023-23939"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/Azure/setup-kubectl/commit/d449d75495d2b9d1463555bb00ca3dca77a42ab6"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/Azure/setup-kubectl"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-732" ],
    "severity" : "LOW",
    "github_reviewed" : true,
    "github_reviewed_at" : "2023-03-07T20:07:27Z",
    "nvd_published_at" : "2023-03-06T19:15:00Z"
  }
}