On May 9, 2024, Microsoft disclosed a security vulnerability that could let attackers gain higher privileges on systems using the Azure Command Line Interface (CLI). Named CVE-2024-43591, this flaw makes it possible for a regular user—or a malicious script—to sneakily elevate their rights. If you use Azure CLI, you’ll want to understand this, patch up, and check your systems.

Let’s break it down in plain English, walk through how the exploit basically works, peek at code snippets, and link to the references.

What can happen: Install software, read files, or change settings like an admin.

- Fixed version: Update to Azure CLI 2.62. or later

Understanding the Vulnerability

Azure CLI is used daily by thousands of admins and devs to manage Azure resources through simple commands. It often interacts with local files and system paths.

The issue in CVE-2024-43591 centers on the way Azure CLI handles plugin installation paths and runs some commands without strict privilege checks. Under certain conditions, a local user can trick the CLI into loading malicious code or running scripts with elevated rights.

How did this happen?

1. Insecure File Permissions: CLI's plugins/extensions/add-ons sometimes install with weak privileges, letting less-privileged users drop files into directories that get loaded on the next CLI run.
2. Privilege Escalation: If someone manages to place a malicious script or binary in a path that’s read by Azure CLI under a privileged context—like when an admin runs the CLI—it can run with the same (admin) rights.

Step-by-Step: Exploiting CVE-2024-43591

Below, I’ll walk you through a simplified attack scenario using harmless code snippets. Do *not* use this maliciously!

Windows: %USERPROFILE%\.azure\cliextensions

- Linux: ~/.azure/cliextensions

But, if system-wide or per-user installs expose these paths, a regular user may write to them.

Example path (Windows)

C:\Users\Alice\.azure\cliextensions

2. Plant a Malicious Extension

A valid Azure CLI extension is just a Python package folder with an __init__.py. Say the attacker drops this file:

malicious_extension/__init__.py

import os
os.system('net user haxor MyPassword123! /add')  # Adds a new admin user

They zip this up and place it in %USERPROFILE%\.azure\cliextensions.

3. Wait for a Privileged CLI Run

If an administrator or ‘SYSTEM’ runs the Azure CLI (like in a scheduled task, deployment script, or support tool), and the CLI loads extensions from that directory, it will execute the attacker's code *with admin rights*.

4. Results

Boom—the local user haxor is created as an admin. The attacker escalated their privileges using just Azure CLI’s mismanaged permissions.

How to Fix or Avoid This

1. Update Now: Download Azure CLI 2.62.+.
2. Check Permissions: Tighten filesystem rights on .azure directories and any global plugin/extension folders.

%USERPROFILE%\.azure\cliextensions

- /home/username/.azure/cliextensions

Search for new admin users or unexpected changes to system files right after running Azure CLI.

Microsoft’s official security page:

CVE-2024-43591 - Azure CLI Elevation of Privilege
- Azure CLI Releases and Change Logs
- MITRE Details: CVE-2024-43591 at CVE.org
- How to manage extensions with Azure CLI

Final Thoughts

Vulnerabilities like CVE-2024-43591 remind us: even friendly tools like Azure CLI can be risky if not secured. Keep your software updated, review extension folders, and don’t run admin tasks unless you must. Staying alert keeps your cloud—and your job—safe.

Timeline

Published on: 10/08/2024 18:15:27 UTC
Last modified on: 10/12/2024 00:00:11 UTC