CVE-2018-2781 in MySQL Server
Summary
by MITRE
Vulnerability in the MySQL Server component of Oracle MySQL (subcomponent: Server: Optimizer). Supported versions that are affected are 5.5.59 and prior, 5.6.39 and prior and 5.7.21 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 3.0 Base Score 4.9 (Availability impacts). CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H).
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 03/02/2023
The vulnerability identified as CVE-2018-2781 resides within the MySQL Server component, specifically within the Server: Optimizer subcomponent of Oracle MySQL database systems. This flaw affects multiple version ranges including 5.5.59 and earlier, 5.6.39 and earlier, and 5.7.21 and earlier versions, representing a significant portion of the MySQL ecosystem that remained vulnerable for extended periods. The vulnerability classification as easily exploitable indicates that attackers with high privileged access and network connectivity can leverage this weakness effectively, making it particularly concerning for database administrators and security professionals managing critical infrastructure. The CVSS 3.0 scoring system assigns a base score of 4.9 with a high availability impact rating, reflecting the potential for complete denial of service conditions that can render database services completely inaccessible to legitimate users. The attack vector requires network access via multiple protocols, suggesting that the vulnerability can be exploited through various communication channels that MySQL typically supports.
The technical nature of this vulnerability stems from flaws within the query optimizer functionality of MySQL Server, which is responsible for determining the most efficient execution path for database queries. When maliciously crafted queries are processed through the optimizer, they can trigger memory corruption or resource exhaustion conditions that lead to system instability. The specific mechanisms involve how the optimizer handles certain complex query structures or data manipulation operations that can cause the server process to enter an inconsistent state. This behavior manifests as either complete system hangs where the database becomes unresponsive or frequent crashes that require manual intervention to restore service availability. The vulnerability's impact on availability represents a critical concern for enterprise environments where database uptime directly correlates with business continuity and operational efficiency. According to CWE classification, this vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and potentially CWE-122, which covers heap-based buffer overflow scenarios that can occur during query processing operations.
The operational impact of CVE-2018-2781 extends far beyond simple service disruption, as database availability is fundamental to virtually all enterprise applications and services. Organizations running affected MySQL versions face significant risk of service degradation or complete outages that can cascade through dependent systems, affecting customer-facing applications, reporting systems, and backend processes that rely on database connectivity. The vulnerability's ability to cause complete DOS conditions means that recovery operations may require system restarts, potential data recovery procedures, and service restoration that can take considerable time. For enterprises with high availability requirements, this vulnerability represents a serious threat to operational resilience and can result in substantial financial losses due to extended downtime periods. The CVSS vector indicates that the vulnerability requires high privilege access, suggesting that attackers typically need valid database credentials or administrative access to exploit the flaw, but once achieved, the impact is severe enough to warrant immediate attention and remediation.
Mitigation strategies for CVE-2018-2781 should prioritize immediate patch deployment across all affected MySQL installations, as Oracle has released security updates to address this specific vulnerability. Organizations should implement comprehensive vulnerability management processes that include regular security assessments and patch deployment schedules to prevent similar issues from occurring in the future. Network segmentation and access control measures should be strengthened to limit the attack surface, ensuring that database servers are not directly exposed to untrusted networks. Additionally, monitoring systems should be enhanced to detect unusual query patterns or resource consumption that might indicate exploitation attempts. The ATT&CK framework's T1070.004 technique for "Indicator Removal on Host" should be considered as part of incident response planning, since attackers may attempt to cover their tracks by manipulating system logs or removing evidence of exploitation. Regular security audits and penetration testing should be conducted to identify and remediate similar vulnerabilities in database configurations, while implementing proper database access controls and privilege management to minimize the potential impact of successful exploitation attempts.