CVE-2023-21963 in MySQL Server
Summary
by MITRE • 04/18/2023
Vulnerability in the MySQL Server product of Oracle MySQL (component: Server: Connection Handling). Supported versions that are affected are 5.7.40 and prior and 8.0.31 and prior. Easily exploitable vulnerability allows high privileged attacker with network access via multiple protocols to compromise MySQL Server. Successful attacks of this vulnerability can result in unauthorized ability to cause a partial denial of service (partial DOS) of MySQL Server. CVSS 3.1 Base Score 2.7 (Availability impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:L).
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Analysis
by VulDB Data Team • 05/12/2023
The vulnerability identified as CVE-2023-21963 represents a critical flaw in Oracle MySQL Server's connection handling mechanism that affects versions 5.7.40 and earlier, as well as 8.0.31 and prior. This issue resides within the Server: Connection Handling component of the MySQL database system, making it particularly dangerous as it targets the fundamental connection management capabilities that underpin database operations. The vulnerability's classification as easily exploitable indicates that attackers with high privileges and network access can leverage this weakness to compromise MySQL Server functionality, potentially leading to significant operational disruptions. The CVSS 3.1 score of 2.7 with a vector of AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:L demonstrates the relatively low complexity required for exploitation while maintaining the high privilege requirement necessary to initiate the attack, suggesting that this vulnerability is primarily targeted at authenticated users who already possess elevated access rights within the network environment.
The technical nature of this vulnerability stems from improper handling of connection states or resources during the MySQL Server's connection management processes, which creates opportunities for attackers to manipulate the server's operational behavior. When exploited, this weakness enables unauthorized partial denial of service conditions that can disrupt database connectivity and reduce the availability of critical services. The partial denial of service impact means that while the entire server may not be completely compromised, specific database operations or connection handling capabilities become impaired, potentially affecting business-critical applications that depend on MySQL database connectivity. This vulnerability specifically targets the availability aspect of the CIA security triad as indicated by the CVSS vector, where the attacker can cause local availability impact (A:L) without requiring user interaction or additional privileges beyond those already established.
The operational impact of CVE-2023-21963 extends beyond simple service disruption, as database availability is fundamental to most enterprise applications and services. Organizations utilizing affected MySQL versions face potential business interruption risks where database connections may be refused or become unresponsive, leading to cascading failures in applications that depend on database operations. The vulnerability's network accessibility through multiple protocols increases its exploitation surface, making it particularly concerning for environments where MySQL servers are exposed to external networks or where multiple network protocols are supported for database connectivity. This weakness aligns with CWE-121, which addresses buffer overflow conditions, and may also relate to CWE-400, dealing with resource exhaustion, as the connection handling mechanisms could be manipulated to exhaust available resources or create unstable connection states that prevent legitimate access to database services.
Organizations should prioritize immediate remediation of this vulnerability by upgrading to MySQL versions that address the connection handling flaw, specifically targeting versions beyond 5.7.40 and 8.0.31. The implementation of network segmentation and access controls can provide additional layers of protection by limiting network access to MySQL servers and reducing the attack surface available to potential exploiters. Regular monitoring of database connection logs and system behavior should be implemented to detect anomalous connection patterns that might indicate exploitation attempts. Security teams should also consider implementing intrusion detection systems that can identify unusual database connection behavior or resource consumption patterns that could signal exploitation of this vulnerability. The ATT&CK framework categorizes this type of vulnerability under T1489, which involves denying service to targets, and potentially T1071, which addresses application layer protocols, as the exploitation involves manipulating network protocols to achieve service disruption. Organizations should conduct thorough vulnerability assessments to ensure all MySQL instances within their environments are properly updated and that access controls are appropriately configured to prevent unauthorized exploitation of this connection handling weakness.