External risk intelligence

Azure Kubernetes Service Confidential Container Elevation of Privilege Vulnerability

CVE advisorySeverity: CRITICAL (CVSS 9.0)

CVE-2024-21400

The vulnerability exists in the confcom Azure CLI extension, which is a local development and management tool used by developers to configure and validate confidential container policies. It is not a service that is deployed to be internet-facing or reachable by remote network traffic in typical production environments.

Path Traversal

Microsoft Confcom

before 0.3.3

Halo Surface Signal: 1 out of 5 — much less likely to be public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

A critical vulnerability has been identified in a Microsoft Azure service that allows for the elevation of privilege. This issue could potentially impact the confidentiality, integrity, and availability of data and operations within affected environments. Determining if your specific Azure deployments are exposed is the primary concern at this time.

Allows unauthorized control over confidential containers.
Affects secure data processing in Azure.
Confirm relevance and exposure in your Azure environment.

Attack Path

How an attacker could exploit the issue

An attacker could exploit this vulnerability by sending specially crafted input to a misconfigured Azure CLI extension. This could allow them to gain elevated privileges within the Azure Kubernetes Service Confidential Container environment, potentially leading to full system compromise.

Requires unauthenticated network access.
Triggered by specially crafted input.
Allows privilege escalation.

Live Threat

Current exploitation, exposure, and threat context

This vulnerability may affect Azure Kubernetes Service confidential containers when specific conditions are met. It could allow an unauthenticated attacker to gain elevated privileges within the service, potentially impacting the confidentiality, integrity, and availability of the containerized environment. The primary risk appears to be related to the local management of confidential container policies rather than a direct internet-facing service exploitation.

Confidential container policies and configurations.
Via a specially crafted request to the confcom extension.
Elevated privileges and service disruption.

Operational Fix

Recommended remediation, mitigation, and detection steps

This vulnerability affects the Microsoft Azure CLI extension for confidential containers. Real-world ownership likely resides with the platform or cloud engineering teams responsible for managing Azure Kubernetes Service and confidential computing configurations. The first practical step is to identify all Azure CLI instances where this extension is installed and used for policy management, confirm if these instances are used by critical services, and then engage the accountable owner to plan remediation.

Cloud platform and security teams own this.
Verify Azure CLI extension installation.
Plan policy and tool updates.

Supplementary metadata

CVSS vector

Validate whether this threat affects your internet-facing exposure.

Halo Threat Intelligence helps prioritize remediation with Halo Surface Signal and H/A/L/O context. Start exposure validation with a free external attack surface trial.

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Frequently asked questions

What is the Microsoft confcom extension?

It is an Azure CLI extension designed for developers. Its primary purpose is to help build, configure, and validate policy files for confidential containers, which are specialized workloads designed to run in isolated, secure execution environments within Azure Kubernetes Service.

What does CVE-2024-21400 mean?

This CVE refers to an Elevation of Privilege vulnerability classified as CWE-22, which involves improper limitation of a pathname to a restricted directory. In the context of the confcom extension, this weakness could allow an attacker to gain unauthorized control or elevated access within the confidential container environment by sending specially crafted input.

How is this vulnerability triggered?

The issue is triggered by supplying specially crafted input to the confcom extension during policy management operations. It does not occur through standard usage of the extension; the input must be specifically designed to exploit the underlying path limitation weakness.

Is my environment at risk from the internet?

According to Halo Surface Signal, this vulnerability is very unlikely to be reachable from the internet. Because confcom is a local management tool for developers rather than a production service, it is typically not exposed to remote network traffic in the way a web server would be.

Do I need to update my Azure CLI installation?

Yes. The first step is to inventory all systems where the confcom extension is installed. Once identified, confirm if these tools are used for critical policy management and coordinate with your cloud engineering or platform teams to update the extension to version 0.3.3 or later to resolve the vulnerability.

References

msrc.microsoft.com/update-guide/vulnerability/CVE-2024-21400

Written by Nicholas Merritt

Nicholas Merritt is VP of Security Solutions at Halo Security. With more than 25 years across application security, vulnerability prioritization, and offensive security, he helps teams translate threat data into practical exposure validation and remediation focus. He authors Halo Threat Intelligence CVE advisories using Halo Surface Signal and H/A/L/O context to prioritize internet-facing risk.