CVE-2016-6662 in MySQL Server
Summary
by MITRE
Oracle MySQL through 5.5.52, 5.6.x through 5.6.33, and 5.7.x through 5.7.15; MariaDB before 5.5.51, 10.0.x before 10.0.27, and 10.1.x before 10.1.17; and Percona Server before 5.5.51-38.1, 5.6.x before 5.6.32-78.0, and 5.7.x before 5.7.14-7 allow local users to create arbitrary configurations and bypass certain protection mechanisms by setting general_log_file to a my.cnf configuration. NOTE: this can be leveraged to execute arbitrary code with root privileges by setting malloc_lib. NOTE: the affected MySQL version information is from Oracle's October 2016 CPU. Oracle has not commented on third-party claims that the issue was silently patched in MySQL 5.5.52, 5.6.33, and 5.7.15.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 11/21/2024
This vulnerability represents a critical privilege escalation flaw in database management systems that affects multiple major database vendors including Oracle MySQL, MariaDB, and Percona Server. The issue stems from improper handling of configuration file parameters that allows local attackers to manipulate system behavior through strategic manipulation of database configuration files. The vulnerability specifically targets the general_log_file parameter which, when improperly controlled, can be exploited to bypass security protections and execute arbitrary code with elevated privileges. This represents a fundamental failure in input validation and privilege management within the database server's configuration handling mechanisms.
The technical exploitation of this vulnerability occurs through manipulation of the my.cnf configuration file where an attacker can set the general_log_file parameter to point to a location they control. This creates a dangerous scenario where the database service can be coerced into writing logs to arbitrary locations, effectively allowing configuration file modification. The vulnerability becomes particularly dangerous when combined with the malloc_lib parameter, which can be used to load malicious shared libraries and execute code with the privileges of the database service. This attack vector operates under the principle of configuration file manipulation and privilege escalation, aligning with CWE-22 (Improper Limitation of a Pathname to a Restricted Directory) and CWE-74 (Improper Neutralization of Special Elements in Output Used by a Downstream Component).
The operational impact of this vulnerability is severe as it allows local users to escalate privileges to root level execution, effectively compromising the entire system. Database services typically run with elevated privileges to perform their functions, and this vulnerability creates a path for local attackers to leverage these elevated permissions for malicious purposes. The exploit chain demonstrates how a seemingly benign configuration parameter can become a critical security weakness when proper input validation and privilege separation are not enforced. Attackers can use this vulnerability to establish persistent access, escalate privileges, and potentially compromise the entire host system. This vulnerability also highlights the importance of proper privilege separation and the dangers of allowing local users to manipulate system configuration files that are processed with elevated privileges.
Mitigation strategies for this vulnerability must address both the immediate configuration handling issues and broader system security practices. Organizations should implement strict file permissions and access controls on database configuration files, ensuring that only authorized users can modify these critical system components. The recommended approach includes applying vendor patches immediately, as Oracle and other vendors have released updates to address this specific issue. Additionally, system administrators should consider implementing privilege separation techniques, where database services run with minimal required privileges rather than root access. Security monitoring should include detection of unauthorized configuration file modifications, particularly around database service configuration files. This vulnerability also underscores the importance of following security best practices such as the principle of least privilege and regular security assessments of database configurations. The ATT&CK framework categorizes this as a privilege escalation technique using configuration file manipulation, making it a critical concern for security teams implementing comprehensive threat detection and response strategies.