CVE-2018-2778 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 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).
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Analysis
by VulDB Data Team • 03/02/2023
The vulnerability identified as CVE-2018-2778 resides within the MySQL Server component, specifically within the Server: Optimizer subcomponent, affecting MySQL versions 5.7.21 and earlier. This represents a significant security flaw that demonstrates how optimization components within database systems can introduce unexpected risks. The vulnerability operates at a foundational level within the database engine, where the optimizer component is responsible for determining the most efficient execution plan for SQL queries. When this optimization logic encounters specific conditions, it can trigger a critical failure in the server's operation.
The technical nature of this vulnerability stems from improper handling of certain query execution paths within the optimizer module. Attackers with high privileged access and network connectivity can exploit this flaw by crafting specific SQL queries that manipulate the optimizer's decision-making process. The vulnerability manifests as a complete denial of service condition where the MySQL server becomes unresponsive or crashes repeatedly, effectively rendering the database service unavailable to legitimate users. This occurs because the optimizer's internal state becomes corrupted during query processing, leading to memory management issues or execution path failures that cannot be recovered from gracefully.
From an operational impact perspective, this vulnerability presents a severe availability risk to organizations relying on MySQL databases, particularly those running affected versions. The CVSS 3.0 score of 4.9 indicates a moderate to high severity threat that can result in complete service disruption. The attack vector requires only network access and high privileges, making it particularly dangerous in environments where administrative accounts might be compromised or where privilege escalation has occurred. Organizations may experience extended downtime, data unavailability, and potential business disruption when this vulnerability is exploited successfully, especially in mission-critical applications where database uptime is essential.
The exploitation of this vulnerability aligns with ATT&CK technique T1499.004, which involves network denial of service attacks, and CWE-121, which addresses stack-based buffer overflow conditions. The vulnerability demonstrates how optimization components within database engines can become attack surfaces when proper input validation and state management are not implemented. Organizations should immediately apply the security patches released by Oracle to address this issue, as the vulnerability cannot be effectively mitigated through configuration changes alone. Additionally, implementing network segmentation and access controls can help reduce the attack surface by limiting which systems can reach the MySQL server and reducing the likelihood of privilege escalation attacks that could lead to exploitation of this vulnerability.