Microsoft's Object Linking and Embedding (OLE) Database (DB) technology is used by many applications and systems to access and manage databases. OLE DB is an important component of the overall data access strategy, allowing users to work with databases in a consistent way across various platforms. However, a newly discovered vulnerability (CVE-2023-38169) exploits a weakness in the OLE DB implementation, allowing an attacker to remotely execute arbitrary code with the potential to wreak havoc on affected systems. In this deep dive, we'll explore the details of the vulnerability, its potential impact, share code snippets to understand the vulnerability better, and examine the available remedies to protect against it.

Exploit Details

The CVE-2023-38169 vulnerability exists due to improper validation of user-supplied input when processing OLE DB queries in the Microsoft Data Access Components (MDAC). A remote attacker with the ability to send a specially crafted query to the vulnerable system can trigger a heap overflow, allowing for Arbitrary Code Execution (ACE), consequently giving the attacker full access to the target system.

The vulnerability exists in the 'msado15.dll' library file, which is used to implement OLE DB queries and is distributed with various software packages, including the Microsoft Data Access Components (MDAC), Microsoft Office, and Microsoft SQL Server. The vulnerability has been confirmed to affect the following versions:

Code Snippet

The following code snippet demonstrates how a vulnerable system might process a malicious OLE DB query, leading to the heap overflow:

// Sample vulnerable method
void ProcessQuery(BSTR bstrQuery)
{
    ...

    // Allocate memory for query processing
    void* pMem = malloc(x200);

    // Copy the input query (bstrQuery) into buffer (pMem)
    memcpy(pMem, bstrQuery, SysStringByteLen(bstrQuery));

    ...
}

In this example, a fixed-size buffer (x200 bytes) is allocated for query processing. However, the user input (bstrQuery) is copied into this buffer without proper length validation. An attacker can send a query long enough to overwrite the buffer, eventually leading to a heap overflow and arbitrary code execution.

Below are the primary sources disclosing and detailing the CVE-2023-38169 vulnerability

- CVE-2023-38169 - MITRE
- Microsoft Security Bulletin MS09-062

Mitigations and Fixes

To protect against the CVE-2023-38169 vulnerability, the following remediation efforts can be undertaken:
1. Apply the patches: Microsoft has released patches to address this vulnerability, available in the Microsoft Security Bulletin MS09-062. It's essential to apply these patches to all affected systems.

2. Restrict network access: Where possible, restrict external access to systems that use OLE DB or have Microsoft Office or SQL Server installed. Employing network segmentation and firewalls can help prevent unauthorized hosts from sending malicious OLE DB queries to the vulnerable systems.

3. Validate input length: Ensure that any software using the OLE DB library properly validates the length of user-supplied input before processing, preventing potential buffer overflow situations.

Conclusion

While the CVE-2023-38169 vulnerability presents a serious risk for systems using Microsoft's OLE DB technology, the availability of patches and other remediation efforts can help organizations protect their systems from potential exploitation. By updating vulnerable systems and employing security best practices, we can mitigate the risks associated with this Remote Code Execution vulnerability.

Timeline

Published on: 08/08/2023 18:15:00 UTC
Last modified on: 08/10/2023 20:40:00 UTC