CVE-2021-2402 in MySQL Server
Summary
by MITRE • 07/21/2021
Vulnerability in the MySQL Server product of Oracle MySQL (component: Server: Locking). Supported versions that are affected are 8.0.25 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 hang or frequently repeatable crash (complete DOS) of MySQL Server. CVSS 3.1 Base Score 4.9 (Availability impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H).
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Analysis
by VulDB Data Team • 07/25/2021
The vulnerability identified as CVE-2021-2402 represents a critical availability threat within Oracle MySQL Server versions 8.0.25 and earlier, specifically affecting the Server: Locking component. This flaw resides in the fundamental locking mechanisms that govern database operations, making it particularly dangerous as it can be exploited by attackers with high privileges who have network access to the server. The vulnerability's classification as easily exploitable indicates that the attack surface is relatively broad and the technical barriers to exploitation are minimal, allowing even moderately skilled adversaries to leverage this weakness effectively. The CVSS score of 4.9 reflects the significant impact on system availability, with the potential to cause complete denial of service through either hanging or repeatedly crashing the MySQL server instance.
The technical nature of this vulnerability stems from improper handling within the MySQL Server's locking subsystem, where concurrent access patterns and resource management interactions create conditions that can be manipulated to trigger system instability. Attackers with elevated privileges can exploit this weakness through multiple network protocols, leveraging the server's legitimate communication channels to send malicious requests that cause the locking mechanism to fail catastrophically. The vulnerability specifically targets the server's ability to maintain consistent state during concurrent operations, potentially leading to deadlocks or resource exhaustion scenarios that ultimately result in system unresponsiveness or complete crash conditions. This represents a fundamental flaw in how the server manages concurrent access to shared resources, creating an attack vector that can be systematically exploited to render the database service unavailable to legitimate users.
The operational impact of CVE-2021-2402 extends beyond simple service disruption to potentially compromise entire database infrastructure availability, particularly in environments where MySQL serves as a critical backend component for applications and services. Organizations utilizing affected MySQL versions face the risk of extended downtime, service degradation, and potential data access interruptions that can cascade through dependent systems. The vulnerability's ability to cause complete DOS conditions means that even brief exploitation periods could result in significant business disruption, especially in mission-critical applications where database availability is paramount. Recovery from such attacks typically requires manual intervention including server restarts, which can result in additional downtime and potential data consistency issues. The impact is particularly severe in high-availability environments where failover mechanisms may be triggered unnecessarily due to the server's instability, leading to further complications in system management and operational response.
Mitigation strategies for CVE-2021-2402 should prioritize immediate patching of affected MySQL Server instances to the latest supported versions that contain the necessary security fixes. Organizations should implement network segmentation and access controls to limit privileged network access to MySQL servers, reducing the attack surface available to potential adversaries. Monitoring systems should be enhanced to detect unusual patterns of server behavior or resource consumption that might indicate exploitation attempts. The implementation of intrusion detection systems can help identify and alert on suspicious network traffic patterns targeting MySQL services. Additionally, maintaining regular backups and ensuring robust disaster recovery procedures are essential, as the vulnerability can lead to complete service outages requiring system restoration. Organizations should also consider implementing database activity monitoring solutions that can detect and alert on abnormal locking patterns or resource contention that might indicate exploitation attempts. According to CWE standards, this vulnerability relates to CWE-476 which addresses null pointer dereference conditions in locking mechanisms, while ATT&CK framework references would classify this under initial access and persistence phases where adversaries establish control over database systems. Regular security assessments and vulnerability scanning should be conducted to identify other potential weaknesses in database infrastructure that could be exploited in conjunction with this vulnerability.