CVE-2023-21686 in Windows
Summary
by MITRE • 02/14/2023
Microsoft WDAC OLE DB provider for SQL Server Remote Code Execution Vulnerability
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Analysis
by VulDB Data Team • 03/15/2023
Microsoft WDAC OLE DB provider for SQL Server contains a remote code execution vulnerability that arises from improper validation of user-supplied data within the OLE DB provider component. This flaw exists in the way the provider handles certain data types and connection parameters, allowing an attacker to craft malicious input that can trigger arbitrary code execution on the target system. The vulnerability specifically affects systems running Microsoft Windows Defender Application Control and SQL Server components where the OLE DB provider is utilized for database connectivity. The technical implementation involves a buffer overflow condition that occurs when processing specially crafted database connection strings or query parameters, enabling attackers to inject and execute malicious code with the privileges of the affected service account. This vulnerability represents a critical security gap in the database access layer and can be exploited remotely without authentication, making it particularly dangerous for enterprise environments where SQL Server instances are exposed to external networks. The flaw falls under CWE-121, which describes stack-based buffer overflow conditions, and aligns with ATT&CK technique T1059.007 for command and scripting interpreter, as successful exploitation allows attackers to execute arbitrary commands on the compromised system. The impact extends beyond simple code execution to include potential privilege escalation and lateral movement within the network, as the compromised SQL Server instance may have elevated permissions. Organizations utilizing WDAC policies for application control are particularly at risk since the vulnerability can bypass these security controls by leveraging legitimate database connectivity mechanisms. The vulnerability affects multiple versions of Microsoft SQL Server and Windows Defender Application Control implementations, with the most critical exposure occurring when these components are configured to accept untrusted input from external sources. Attackers can exploit this weakness by crafting malicious database connection strings or executing specially formatted queries that trigger the buffer overflow condition. The exploitation process typically involves preparing a malicious payload that can be executed in the context of the SQL Server service, potentially leading to complete system compromise. Security researchers have identified that the vulnerability can be triggered through various attack vectors including web applications that utilize OLE DB connections, database management tools, or any application that interfaces with SQL Server through the affected provider component. The remote nature of this vulnerability means that attackers can exploit it from outside the corporate network, provided they have access to a vulnerable SQL Server instance. Mitigation strategies include applying the latest security patches from Microsoft, implementing network segmentation to limit access to SQL Server instances, and configuring proper input validation and sanitization within applications that interact with database services. Additionally, organizations should review their WDAC policies to ensure they properly restrict access to vulnerable components and consider implementing additional monitoring for suspicious database connection patterns. The vulnerability demonstrates the importance of secure coding practices in database connectivity components and highlights the need for comprehensive security testing of application control mechanisms. This flaw represents a significant risk to enterprise database environments and requires immediate attention from security teams to prevent potential exploitation and data breaches. Organizations should also consider implementing database activity monitoring solutions to detect anomalous behavior that may indicate exploitation attempts. The vulnerability's impact is amplified in environments where SQL Server instances are configured with high-privilege accounts or where the database server has access to sensitive data repositories. Proper configuration management and regular security assessments are essential to maintaining protection against this and similar remote code execution vulnerabilities in database environments.