CVE-2020-14868 in MySQL Server
Summary
by MITRE • 10/21/2020
Vulnerability in the MySQL Server product of Oracle MySQL (component: Server: Optimizer). Supported versions that are affected are 8.0.21 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 • 11/24/2020
The vulnerability identified as CVE-2020-14868 represents a significant availability threat within Oracle MySQL Server versions 8.0.21 and earlier, specifically affecting the Server: Optimizer component. This weakness stems from insufficient input validation during query optimization processes, creating a pathway for malicious actors to manipulate the server's execution flow. The vulnerability's classification as easily exploitable indicates that attackers with high privileged access and network connectivity can leverage this flaw without requiring extensive technical expertise or specialized tools. The attack surface encompasses multiple network protocols, making the vulnerability particularly concerning for environments where MySQL servers are exposed to untrusted networks or where privilege escalation has occurred within the system.
The technical implementation of this vulnerability involves a specific flaw in how the MySQL optimizer handles certain query structures, leading to potential buffer overflows or memory corruption during the optimization phase. When exploited, the vulnerability triggers a condition that causes the MySQL server process to either hang indefinitely or crash repeatedly, resulting in a complete denial of service scenario. This behavior aligns with the CVSS 3.1 scoring system, where the base score of 4.9 reflects the high availability impact and the ease of exploitation. The vulnerability's characteristics demonstrate a clear relationship to CWE-121, which addresses stack-based buffer overflow conditions, and potentially CWE-125, which covers out-of-bounds read scenarios that can occur during memory management operations. The availability impact is particularly severe as it completely compromises the database server's operational capacity, rendering all dependent applications unable to access critical data services.
From an operational standpoint, the implications of CVE-2020-14868 extend beyond simple service disruption to encompass broader business continuity concerns. Organizations relying on MySQL for critical database operations face potential revenue losses, customer service degradation, and increased operational overhead during recovery periods. The vulnerability's susceptibility to network-based attacks means that even systems behind firewalls or within private networks could be compromised if proper access controls are not maintained. Security teams must consider the ATT&CK framework's T1059.006 technique related to command and scripting interpreter usage, as attackers might leverage this vulnerability to maintain persistent access through repeated exploitation attempts. The complete denial of service condition also creates opportunities for attackers to conduct extended disruption campaigns, potentially masking other malicious activities or creating cover for more sophisticated attacks. Organizations should implement comprehensive monitoring solutions to detect unusual patterns of server crashes or hangs that could indicate exploitation attempts. The vulnerability's exploitation requires only high privileged access, meaning that internal threats or compromised accounts with elevated privileges pose significant risks. System administrators must also consider the broader implications for database replication, backup operations, and high availability configurations that may fail during the vulnerability's exploitation phase.
Mitigation strategies for CVE-2020-14868 should prioritize immediate patching of affected MySQL Server installations to version 8.0.22 or later, where the vulnerability has been addressed through enhanced input validation and memory management controls. Network segmentation and access control measures should be implemented to limit the attack surface, ensuring that only authorized systems can establish connections to MySQL servers. Regular security assessments should include vulnerability scanning procedures specifically targeting MySQL components and their optimization engines. The implementation of intrusion detection systems capable of identifying patterns associated with the vulnerability's exploitation can provide early warning capabilities. Additionally, organizations should establish robust backup and recovery procedures that account for potential denial of service scenarios, ensuring that database availability can be restored quickly in the event of successful exploitation attempts. The vulnerability's classification as a high-privilege attack vector necessitates strict access control policies and regular privilege audits to minimize the risk of unauthorized access to database servers. Organizations should also consider implementing database activity monitoring solutions that can detect anomalous query patterns that might indicate exploitation attempts, particularly focusing on optimization-related operations that could trigger the vulnerable code paths.