CVE-2023-21685 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
The Microsoft WDAC OLE DB provider for SQL Server remote code execution vulnerability represents a critical security flaw that allows attackers to execute arbitrary code on affected systems through maliciously crafted database operations. This vulnerability specifically impacts environments where the Windows Defender Application Control (WDAC) OLE DB provider is utilized for SQL Server database connectivity, creating a potential attack surface that could be exploited by threat actors to gain unauthorized access to sensitive data and system resources. The flaw stems from improper input validation within the OLE DB provider component that handles database connection requests and query processing, enabling malicious data payloads to bypass security controls and execute code with the privileges of the affected service account. This vulnerability is particularly concerning as it leverages the trusted database connectivity mechanisms that organizations rely upon for business operations, making detection and mitigation more challenging.
The technical exploitation of this vulnerability occurs through crafted OLE DB connection strings or database queries that manipulate the provider's handling of input parameters. When the WDAC OLE DB provider processes these malformed inputs, it fails to properly sanitize or validate the data before executing database operations, creating opportunities for command injection attacks. The vulnerability exists at the interface level between the database connectivity layer and the application control mechanisms, where insufficient validation allows attacker-controlled data to flow into execution contexts. This flaw aligns with CWE-74 standards for improper neutralization of special elements used in data queries, specifically targeting the OLE DB provider's input processing routines. The attack vector typically involves an attacker who has gained access to database credentials or can influence database connection parameters, potentially through phishing, credential theft, or other initial compromise techniques that align with ATT&CK technique T1566 for credential harvesting.
The operational impact of this vulnerability extends beyond immediate code execution capabilities to encompass potential data breaches, system compromise, and business disruption across enterprise environments. Organizations utilizing WDAC policies for SQL Server connectivity face significant risk as attackers could exploit this vulnerability to escalate privileges, access sensitive databases, or deploy additional malware through compromised database connections. The vulnerability affects systems where WDAC is actively enforcing application control policies, making it particularly dangerous in security-hardened environments where traditional attack vectors may be blocked. Successful exploitation could result in unauthorized data access, data modification, or complete system compromise, depending on the privileges associated with the database connection account. The impact is further amplified when considering that many organizations implement WDAC policies to prevent unauthorized applications from executing, creating a false sense of security that this vulnerability can bypass. This scenario creates a situation where security controls designed to prevent malicious software execution become ineffective against this specific vulnerability, as the attack occurs within the legitimate database connectivity framework.
Mitigation strategies for this vulnerability should prioritize immediate patch deployment from Microsoft as the primary defensive measure, while organizations implement additional layered security controls to reduce attack surface exposure. The recommended approach includes applying the relevant security updates from Microsoft's monthly release cycle, which typically address the input validation flaws in the OLE DB provider component. Network segmentation and database access controls should be strengthened to limit the potential impact of successful exploitation, including implementing least privilege principles for database accounts and restricting direct database connections from untrusted networks. Organizations should also consider implementing database activity monitoring solutions that can detect anomalous connection patterns or query execution that might indicate exploitation attempts. Additional protective measures include disabling unnecessary database connectivity features, implementing strict input validation at application level, and conducting regular security assessments of database configurations to identify potential weaknesses in the WDAC policy implementations. These controls align with ATT&CK techniques for defense evasion and privilege escalation, ensuring that even if exploitation occurs, the attacker's ability to move laterally or maintain persistence is significantly reduced. Security teams should also establish incident response procedures specifically addressing database connectivity vulnerabilities and maintain detailed logging of all database connection activities to support forensic analysis in case of compromise.