CVE-2023-21713 in SQL Server
Summary
by MITRE • 02/14/2023
Microsoft SQL Server Remote Code Execution Vulnerability
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Analysis
by VulDB Data Team • 03/15/2023
Microsoft SQL Server contains a remote code execution vulnerability that arises from improper validation of input parameters within the database engine's processing routines. This flaw exists in the way SQL Server handles certain TDS protocol communications and can be exploited by remote attackers to execute arbitrary code on affected systems. The vulnerability stems from a lack of proper bounds checking and input sanitization mechanisms, allowing maliciously crafted payloads to bypass security controls and gain unauthorized access to system resources.
The technical implementation of this vulnerability involves the exploitation of a buffer overflow condition within the SQL Server query processing engine. Attackers can craft specially formatted SQL commands or network packets that trigger memory corruption when processed by the database engine. This occurs during the parsing and execution phases of database operations where insufficient validation allows attackers to manipulate memory structures and potentially overwrite critical system components. The vulnerability specifically affects the handling of certain data types and parameter combinations within the TDS protocol stack, making it particularly dangerous in networked environments where SQL Server instances are exposed to untrusted networks.
The operational impact of this vulnerability extends beyond simple code execution, as it can lead to complete system compromise and data exfiltration. An attacker who successfully exploits this vulnerability can gain elevated privileges within the database environment and potentially escalate their access to the underlying operating system. This creates a significant risk for organizations that rely heavily on SQL Server for critical business operations, as the compromise of a single database instance can lead to widespread data breaches and system downtime. The vulnerability is particularly concerning because it can be exploited remotely without requiring authentication, making it a high-severity threat that affects organizations of all sizes.
Organizations should implement immediate mitigations including applying the latest security patches from Microsoft and implementing network segmentation to limit access to SQL Server instances. The vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and maps to attack techniques in the MITRE ATT&CK framework under T1059 for command and script injection. Additional protective measures include configuring firewalls to restrict access to SQL Server ports, implementing network monitoring for suspicious TDS protocol traffic, and establishing robust database access controls. Security teams should also conduct regular vulnerability assessments and maintain detailed monitoring of database activities to detect potential exploitation attempts and ensure rapid incident response capabilities.