On April 9, 2024, Microsoft published an important security advisory about a critical vulnerability, CVE-2024-28942, affecting the Microsoft OLE DB Driver for SQL Server. This vulnerability can allow attackers to execute remote code on your systems if exploited successfully. In this long read, we’ll break down what this means, how exploitation works, and share exclusive tips including code snippets and references.

What is OLE DB Driver for SQL Server?

Microsoft's OLE DB Driver for SQL Server is a data access interface that lets Windows applications communicate with SQL Server databases. It’s used in countless enterprise setups, especially with legacy applications.

Vulnerabilities in this driver can be severe, since the driver often runs with elevated privileges and is connected to sensitive data.

Understanding CVE-2024-28942

Official Description (Microsoft Security Update Guide):

> “A remote code execution vulnerability exists in Microsoft OLE DB Driver for SQL Server... An attacker could exploit this vulnerability by sending a specially crafted request to an affected driver.”

Severity: *Critical*
CVSS Score: *8.8*
Component Affected: msodbcsql, msoledbsql
Patched: Yes (April 2024 update)

How the Exploit Works

1. Network Access Required: The attacker must be able to communicate with the target application over the network.
2. Crafted Request: The attacker sends a specially crafted payload or SQL statement to the OLE DB Driver via the app.
3. Trigger Memory Corruption: The malicious request exploits a flaw in the driver's parsing logic, causing memory corruption.
4. Remote Code Execution: With memory control, the attacker executes arbitrary code as the user running the application.

Proof of Concept (PoC) – Simplified Example

Below is a basic PoC (for educational purposes only) showing how an attacker might attempt to exploit a vulnerable application using the OLE DB driver.

Suppose you have a .NET application using the OLE DB driver

using System.Data.OleDb;

string connString = "Provider=MSOLEDBSQL;Data Source=SERVER;Initial Catalog=DB;User ID=sa;Password=Your_password123;";
using (OleDbConnection conn = new OleDbConnection(connString))
{
    conn.Open();
    string userInput = "'; exec xp_cmdshell('calc.exe'); --";
    string sqlCommand = "SELECT * FROM Users WHERE Name = '" + userInput + "'";
    using (OleDbCommand cmd = new OleDbCommand(sqlCommand, conn))
    using (OleDbDataReader reader = cmd.ExecuteReader())
    {
        // ...
    }
}

Exploit detail:
If the application does not sanitize user input, an attacker can inject commands like xp_cmdshell, which spawns calc.exe. In this case, the underlying OLE DB driver can be tricked into executing shell commands because of the memory corruption vulnerability.

Note:
The real CVE-2024-28942 exploit is more complicated and may not directly relate to SQL injection, but the above shows the kind of risk you face when an RCE bug hits a data access driver.

Mitigation

- Update immediately: Download and install the patched driver here.

References

- Microsoft Security Advisory for CVE-2024-28942
- Download OLE DB Driver for SQL Server
- SQL Server Security Best Practices

Final Thoughts

CVE-2024-28942 is very dangerous because it impacts a core database connectivity component used globally. If you haven’t yet updated your drivers, do so now. Always validate and sanitize input, restrict xp_cmdshell, and keep an eye on future advisories from Microsoft.

Protect your servers, patch often, and never underestimate “just a driver” vulnerabilities. Spread the word, and stay safe!

Timeline

Published on: 04/09/2024 17:15:56 UTC
Last modified on: 04/10/2024 13:24:00 UTC