CVE-2018-2775 in MySQL Server
Summary
by MITRE
Vulnerability in the MySQL Server component of Oracle MySQL (subcomponent: Server: Optimizer). Supported versions that are affected are 5.7.21 and prior. Easily exploitable vulnerability allows low 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 6.5 (Availability impacts). CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H).
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Analysis
by VulDB Data Team • 03/02/2023
The vulnerability identified as CVE-2018-2775 resides within the MySQL Server component, specifically within the Server: Optimizer subcomponent, affecting MySQL versions 5.7.21 and earlier. This represents a critical availability risk that demonstrates how optimization routines within database systems can introduce significant security weaknesses. The flaw manifests in the query optimizer's handling of certain complex SQL operations, creating a scenario where malformed or specially crafted queries can trigger unexpected behavior within the database engine's execution path. The vulnerability's classification as easily exploitable indicates that attackers with minimal privileges and network access can leverage this weakness without requiring specialized tools or extensive reconnaissance.
The technical nature of this vulnerability stems from improper handling of memory allocation and execution flow within the optimizer module when processing specific query patterns. Attackers can construct SQL statements that, when executed against the vulnerable MySQL server, cause the optimizer to enter an infinite loop or consume excessive system resources, ultimately leading to a denial of service condition. The vulnerability's impact is particularly severe because it affects the core database functionality, specifically the query processing capabilities that are fundamental to database operations. This issue operates at the intersection of software engineering and security, where performance optimization features inadvertently create attack surfaces that can be exploited to disrupt service availability.
The operational impact of CVE-2018-2775 extends beyond simple service disruption to potentially compromise entire database infrastructures. When successfully exploited, the vulnerability can cause complete database server crashes that require manual intervention to restore service, resulting in significant downtime and potential data integrity concerns. Organizations running affected MySQL versions face substantial risk as this vulnerability allows attackers with low privileges to cause persistent disruptions that can affect business operations, data access, and system availability. The CVSS 3.0 score of 6.5 reflects the balance between the ease of exploitation and the severity of impact, indicating that while the attack vector is accessible, the consequences are severe enough to warrant immediate attention.
Security practitioners should consider this vulnerability in the context of broader attack patterns documented in the ATT&CK framework, particularly within the privilege escalation and denial of service categories. The vulnerability aligns with CWE-121, which addresses buffer overflow conditions, and CWE-362, which covers concurrent execution issues. Organizations should implement immediate mitigation strategies including upgrading to MySQL versions 5.7.22 or later where this vulnerability has been addressed, applying the relevant security patches, and implementing network segmentation to limit access to database servers. Additionally, monitoring for unusual query patterns and implementing proper access controls can help detect and prevent exploitation attempts, while regular vulnerability assessments should include checks for similar optimizer-related issues that could present analogous risks.