CVE-2024-37331 - SQL Server Native Client OLE DB Provider Remote Code Execution Vulnerability Explained

In June 2024, Microsoft disclosed a critical vulnerability—CVE-2024-37331—that affects the SQL Server Native Client OLE DB provider. This flaw can allow a remote and unauthenticated attacker to execute code on a vulnerable system, essentially taking over servers and databases. In this post, we’ll break down what CVE-2024-37331 is, show technical code snippets, explain how attackers exploit it, and help you understand the risks and fixes.

What Is CVE-2024-37331?

CVE-2024-37331 is a "Remote Code Execution" (RCE) vulnerability found in the OLE DB provider (SQLNCLI11.DLL) that comes with Microsoft SQL Server Native Client versions prior to the patched release. If successfully exploited, it can let attackers run code with the same permissions as the service using the OLE DB Provider—often SYSTEM or high-privileged database accounts.

How Does the Exploit Work?

OLE DB providers allow Windows applications to connect and communicate with databases. If an attacker can trick an application to process crafted data (often through network-accessible services or malicious files), they can corrupt memory, overwrite critical areas, and run arbitrary code.

Attack scenario example

- The attacker sends a specially crafted connection string or payload using, say, a PowerShell script or web application that uses SQL Server Native Client.

Exploit Code Snippet

While we won’t share a full exploit (for safety), here is a simplified version of the approach an attacker may use—just to illustrate the technique and help defenders understand what to look for.

# Example: Malicious PowerShell using SQL Server Native Client OLE DB Provider

$provider = "Provider=SQLNCLI11;Data Source=VULNERABLE_SERVER;Initial Catalog=master;Integrated Security=SSPI;"
$payload = "'; -- Malicious Input here "  # This can be extended to trigger the vulnerability

# This attempts to open a database connection with a crafted string
$conn = New-Object System.Data.OleDb.OleDbConnection($provider + "User ID=attacker;Password=" + $payload)
try {
    $conn.Open()
} catch {
    Write-Host "Potential vulnerability triggered, check for abnormal behavior."
}

> Note: The actual attack would use more sophisticated payloads, but this shows how simply using a bad input can trigger the bug.

Suspicious activity involving OLE DB connection attempts.

- Abnormal events in the Windows Event Log around database service failures or memory corruption errors.

Apply Patches:

Microsoft has released security updates—install them as soon as possible! Find the official update here:
- Microsoft Security Update Guidance – CVE-2024-37331

Microsoft Security Response Center:

CVE-2024-37331

NVD Entry:

NIST NVD - CVE-2024-37331

Microsoft Docs:

Protecting applications that use SQL Server Native Client

Final Thoughts

CVE-2024-37331 is a major threat to organizations using Microsoft SQL Server Native Client. If left unpatched, attackers can run dangerous code remotely and compromise your entire SQL environment. Always keep your systems updated and check connections using OLE DB, as this vector is popular for attackers looking to break into corporate databases.

Timeline

Published on: 07/09/2024 17:15:22 UTC
Last modified on: 09/03/2024 22:28:46 UTC