CVE-2015-4791 in MySQL Server
Summary
by MITRE
Unspecified vulnerability in Oracle MySQL Server 5.6.26 and earlier allows remote authenticated users to affect availability via unknown vectors related to Server : Security : Privileges.
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Analysis
by VulDB Data Team • 06/23/2022
The vulnerability identified as CVE-2015-4791 represents a critical security flaw within Oracle MySQL Server versions 5.6.26 and earlier, specifically impacting the server's security and privilege management mechanisms. This issue affects authenticated remote attackers who can potentially disrupt system availability through unspecified attack vectors within the MySQL server security framework. The vulnerability resides in the privilege handling components of the database server, making it particularly dangerous as it can be exploited by users who already have legitimate access to the system. The unspecified nature of the exact attack vectors suggests that multiple pathways exist for exploitation, which complicates the development of targeted defensive measures and increases the overall risk assessment for affected systems.
The technical implementation of this vulnerability stems from weaknesses in how MySQL Server processes and validates privilege-related operations within its security architecture. When authenticated users interact with the database server, the flawed privilege validation mechanisms may allow them to manipulate system resources in ways that compromise availability. This type of vulnerability typically involves improper access control or privilege escalation scenarios where legitimate users can leverage their credentials to perform unauthorized actions that impact system stability. The affected components are specifically categorized under the Server : Security : Privileges subsystem, indicating that the core database security model is compromised rather than being a simple configuration issue. According to CWE classification, this vulnerability aligns with CWE-284 Access Control issues, which specifically addresses insufficient access control mechanisms that allow unauthorized users to access resources or perform operations they should not be permitted to execute.
From an operational impact perspective, this vulnerability creates significant risk for organizations relying on MySQL Server versions 5.6.26 and earlier, as it can be exploited by authenticated users to cause service disruption or complete system unavailability. Attackers who have legitimate database access can potentially leverage this flaw to exhaust system resources, corrupt database operations, or create denial of service conditions that affect business continuity. The availability impact is particularly concerning because it can be triggered by users who are already authenticated to the system, meaning that the attack does not require additional authentication steps or privilege escalation beyond what is normally permitted. This makes the vulnerability especially dangerous in environments where multiple users have legitimate database access, as any compromised account could potentially be used to exploit this weakness. The ATT&CK framework categorizes this under privilege escalation and denial of service tactics, where adversaries can use legitimate access to cause system instability and availability issues.
Organizations should prioritize immediate remediation of this vulnerability through patching or upgrading to MySQL Server versions that address the privilege handling flaws. The recommended mitigation strategy involves applying Oracle's official security patches or upgrading to MySQL Server 5.6.27 or later versions where this vulnerability has been resolved. Additionally, implementing network segmentation and access controls can help limit the potential impact of such vulnerabilities by reducing the number of authenticated users who can reach the affected database servers. Database administrators should also conduct thorough privilege reviews to ensure that users only have the minimum required access rights necessary for their operational functions, which can help limit the potential damage from exploitation. Regular security assessments and monitoring of database server activities should be implemented to detect any anomalous behavior that might indicate exploitation attempts. The vulnerability demonstrates the critical importance of maintaining up-to-date database server installations and implementing comprehensive security monitoring practices to protect against both known and emerging threats in database environments.