Login Sign Up

CVE-2021-31938

7.3 HIGH

📋 TL;DR

This vulnerability in the Microsoft VsCode Kubernetes Tools Extension allows attackers to execute arbitrary code with elevated privileges by exploiting a flaw in how the extension handles Kubernetes configurations. It affects users who have installed the vulnerable extension in Visual Studio Code. Successful exploitation could lead to complete system compromise.

💻 Affected Systems

Products:
  • Microsoft Visual Studio Code Kubernetes Tools Extension
Versions: Versions prior to 1.3.0
Operating Systems: Windows, Linux, macOS
Default Config Vulnerable: ⚠️ Yes
Notes: Only affects systems where the Kubernetes Tools extension is installed in Visual Studio Code. The vulnerability is present in the extension itself, not the core VS Code application.

📦 What is this software?

Kubernetes Tools by Microsoft

View all CVEs affecting Kubernetes Tools →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Full system compromise with attacker gaining administrative privileges, allowing installation of malware, data theft, and persistence mechanisms.

🟠

Likely Case

Local privilege escalation allowing attackers to execute code with higher privileges than their current user account.

🟢

If Mitigated

Limited impact if extension is not installed or proper security controls restrict execution of untrusted configurations.

🌐 Internet-Facing: LOW - This is primarily a local privilege escalation vulnerability requiring local access or social engineering to exploit.
🏢 Internal Only: MEDIUM - Internal users with access to vulnerable systems could exploit this for privilege escalation attacks.

🎯 Exploit Status

Public PoC: ✅ No
Weaponized: UNKNOWN
Unauthenticated Exploit: ✅ No
Complexity: MEDIUM

Exploitation requires the attacker to have some level of access to the system and ability to manipulate Kubernetes configuration files that the extension processes.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Version 1.3.0 and later

Vendor Advisory: https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31938

Restart Required: No

Instructions:

1. Open Visual Studio Code. 2. Go to Extensions view (Ctrl+Shift+X). 3. Search for 'Kubernetes'. 4. Click Update on the Kubernetes Tools extension. 5. Alternatively, uninstall and reinstall the extension to get latest version.

🔧 Temporary Workarounds

Disable Kubernetes Tools Extension

all

Temporarily disable the vulnerable extension until patching is possible

code --disable-extension ms-kubernetes-tools.vscode-kubernetes-tools

Uninstall Extension

all

Remove the vulnerable extension completely

code --uninstall-extension ms-kubernetes-tools.vscode-kubernetes-tools

🧯 If You Can't Patch

  • Restrict user permissions to prevent execution of untrusted Kubernetes configuration files
  • Implement application whitelisting to control which extensions can be installed and executed

🔍 How to Verify

Check if Vulnerable:

Check the installed version of Kubernetes Tools extension in VS Code Extensions view. If version is below 1.3.0, system is vulnerable.

Check Version:

code --list-extensions --show-versions | findstr kubernetes

Verify Fix Applied:

Verify Kubernetes Tools extension shows version 1.3.0 or higher in VS Code Extensions view.

📡 Detection & Monitoring

Log Indicators:

  • Unusual extension activity in VS Code logs
  • Suspicious Kubernetes configuration file processing

Network Indicators:

  • Unusual outbound connections from VS Code process

SIEM Query:

Process: 'code.exe' AND CommandLine: '*kubernetes*' AND Version: '<1.3.0'

📊 Metadata

CVE ID: CVE-2021-31938
CVSS v3 Score: 7.3 (HIGH)
CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H
Published: June 8, 2021
Last Updated: November 21, 2024

🔗 References

📤 Share & Export

📄 Export Markdown 📋 Export JSON