CVE-2019-9193 in PostgreSQL
Summary
by MITRE
In PostgreSQL 9.3 through 11.2, the "COPY TO/FROM PROGRAM" function allows superusers and users in the 'pg_read_server_files' group to execute arbitrary code in the context of the database's operating system user. This functionality is enabled by default and can be abused to run arbitrary operating system commands on Windows, Linux, and macOS.
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Analysis
by VulDB Data Team • 04/24/2025
The vulnerability identified as CVE-2019-9193 represents a critical privilege escalation flaw in PostgreSQL database systems ranging from version 9.3 through 11.2. This vulnerability resides in the COPY TO/FROM PROGRAM functionality which was designed to facilitate data transfer operations between database tables and external programs. The flaw allows authenticated users with superuser privileges or membership in the 'pg_read_server_files' group to execute arbitrary operating system commands through the database engine, effectively bypassing traditional database security boundaries and creating a severe attack surface that can be exploited across multiple operating systems including Windows, Linux, and macOS. The vulnerability is particularly concerning because this functionality is enabled by default within the PostgreSQL configuration, meaning that organizations may be exposed without explicit configuration changes.
The technical implementation of this vulnerability stems from the improper handling of command execution within PostgreSQL's COPY functionality. When users execute COPY FROM PROGRAM or COPY TO PROGRAM commands, the system allows specification of operating system commands through the program parameter. The flaw occurs because the database engine does not properly validate or sanitize the command strings passed to the operating system shell, enabling command injection attacks. This represents a classic command injection vulnerability that aligns with CWE-78, which specifically addresses improper neutralization of special elements used in OS commands. Attackers can leverage this functionality to execute arbitrary commands with the privileges of the database service account, which typically runs with elevated system permissions.
The operational impact of CVE-2019-9193 extends beyond simple privilege escalation to encompass complete system compromise potential. An attacker with access to a database user account that has superuser privileges or membership in the 'pg_read_server_files' group can execute commands such as reading sensitive files, executing system binaries, establishing reverse shells, or performing lateral movement within the network. This vulnerability directly maps to several ATT&CK techniques including privilege escalation through command execution and lateral movement via system commands. The default-enabled nature of this feature means that organizations with standard PostgreSQL installations are automatically vulnerable, creating a significant risk for database administrators who may not be aware of this potential attack vector. The vulnerability can be exploited to gain unauthorized access to sensitive data, manipulate database contents, or establish persistent access points within the network infrastructure.
Mitigation strategies for CVE-2019-9193 require immediate attention from database administrators and security teams. The most effective approach involves upgrading to PostgreSQL versions 11.3 or later where this vulnerability has been addressed through enhanced command validation and execution controls. Organizations should also implement strict access controls by limiting superuser privileges and removing unnecessary users from the 'pg_read_server_files' group. Database administrators should disable the COPY TO/FROM PROGRAM functionality entirely if it is not required for business operations, which can be achieved through configuration changes or by using pg_hba.conf settings to restrict access. Additionally, implementing network segmentation, monitoring for unusual database activity, and conducting regular security audits can help detect potential exploitation attempts. The vulnerability demonstrates the importance of secure coding practices and proper input validation in database systems, as highlighted by the CWE classification and the ATT&CK framework's recognition of such privilege escalation techniques. Organizations should also consider implementing database activity monitoring solutions that can detect suspicious COPY command executions and alert security teams to potential exploitation attempts.