CVE-2018-2665 in MySQL Server
Summary
by MITRE
Vulnerability in the MySQL Server component of Oracle MySQL (subcomponent: Server: Optimizer). Supported versions that are affected are 5.5.58 and prior, 5.6.38 and prior and 5.7.20 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).
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 01/31/2021
The vulnerability identified as CVE-2018-2665 resides within the MySQL Server component, specifically within the Server: Optimizer subcomponent, representing a critical availability threat that affects multiple version ranges including 5.5.58 and earlier, 5.6.38 and earlier, and 5.7.20 and earlier. This flaw manifests as a denial of service condition that can be exploited by low-privileged attackers who possess network access through various protocols, making it particularly dangerous in environments where MySQL servers are exposed to untrusted networks. The vulnerability's classification as easily exploitable indicates that attackers require minimal privileges and sophisticated techniques to trigger the flaw, which can be leveraged across multiple network protocols to compromise the target MySQL server.
The technical nature of this vulnerability stems from improper handling within the query optimizer module of MySQL, where specific query patterns can trigger memory corruption or resource exhaustion conditions that lead to server crashes or hangs. When exploited, the vulnerability causes a complete denial of service condition that can result in either a temporary hang of the MySQL server process or a frequently repeatable crash that requires manual intervention to restore service. The CVSS 3.0 scoring of 6.5 reflects the availability impact severity, with the vector AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H indicating network accessibility with low attack complexity, requiring only low privileges, no user interaction, and resulting in high availability impact without compromising confidentiality or integrity. This vulnerability directly maps to CWE-121, which describes heap-based buffer overflow conditions, and aligns with ATT&CK technique T1499.004 for network denial of service attacks.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise entire database infrastructure availability, particularly in mission-critical applications where MySQL servers handle transactional data processing. Organizations utilizing affected MySQL versions face significant risk of service interruptions that can cascade into broader business operations, especially in environments where database availability is paramount for application functionality. The vulnerability's ability to cause frequent crashes means that administrators must implement continuous monitoring and rapid recovery procedures to maintain service availability. Attackers can exploit this flaw repeatedly without detection, making it particularly dangerous for environments where automated monitoring is insufficient to prevent repeated exploitation attempts. Mitigation strategies should include immediate patch application to the affected MySQL versions, implementation of network segmentation to limit access to MySQL services, and deployment of intrusion detection systems to monitor for exploitation attempts. Additionally, organizations should consider implementing database firewalls and query filtering mechanisms to prevent exploitation through malformed queries, while maintaining regular backups and disaster recovery procedures to minimize business impact from potential exploitation events.