CVE-2018-2776 in MySQL Server
Summary
by MITRE
Vulnerability in the MySQL Server component of Oracle MySQL (subcomponent: Group Replication GCS). Supported versions that are affected are 5.7.21 and prior. Easily exploitable vulnerability allows high privileged attacker with network access via XCom 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).
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 03/02/2023
The vulnerability identified as CVE-2018-2776 resides within Oracle MySQL's Group Replication Global Configuration Service component, specifically affecting MySQL Server versions 5.7.21 and earlier. This flaw represents a significant security weakness that can be exploited by attackers with elevated privileges and network access to the XCom interface. The Group Replication feature enables high availability and data consistency across MySQL instances, making this vulnerability particularly concerning for production environments that rely on these replication mechanisms. The vulnerability's classification as easily exploitable indicates that attackers with minimal technical expertise can leverage this weakness to compromise system availability.
The technical nature of this vulnerability stems from improper handling of certain network communication patterns within the Group Replication GCS subsystem. When an attacker with high privileges accesses the MySQL server through the XCom interface, they can craft specific network requests that trigger a condition leading to server instability. The flaw manifests as a complete denial of service scenario where the MySQL server either hangs indefinitely or experiences frequently repeatable crashes. This behavior directly correlates with the CVSS 3.0 base score of 4.9, which reflects the availability impact severity. The vulnerability's attack vector requires network access and authentication privileges, placing it in the high privilege category according to the CVSS scoring system.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise entire database infrastructure reliability. Organizations utilizing MySQL Group Replication for high availability configurations face significant risk as this vulnerability can be leveraged to create persistent service interruptions that may affect business continuity. The complete denial of service condition means that database transactions cannot proceed normally, potentially leading to cascading failures in applications that depend on MySQL availability. This vulnerability particularly affects systems where Group Replication is deployed for mission-critical operations, as the repeated crashes or hanging behavior can be difficult to recover from automatically without manual intervention.
Mitigation strategies for CVE-2018-2776 primarily involve upgrading to MySQL Server versions that have addressed this vulnerability, specifically versions beyond 5.7.21. Organizations should also implement network segmentation to limit access to the XCom interface and restrict authentication privileges to only necessary administrative accounts. The principle of least privilege should be strictly enforced, ensuring that only authorized personnel with legitimate administrative needs can access the Group Replication components. Additionally, monitoring systems should be configured to detect unusual patterns in MySQL server behavior that might indicate exploitation attempts, as the vulnerability's impact is typically evident through service interruptions or performance degradation. This vulnerability aligns with CWE-119, which addresses improper access to memory, and maps to ATT&CK technique T1499.004 for network denial of service attacks. Organizations should also consider implementing intrusion detection systems to monitor for patterns consistent with exploitation attempts against Group Replication interfaces.