CVE-2016-0766 in PostgreSQL
Summary
by MITRE • 01/25/2023
PostgreSQL before 9.1.20, 9.2.x before 9.2.15, 9.3.x before 9.3.11, 9.4.x before 9.4.6, and 9.5.x before 9.5.1 does not properly restrict access to unspecified custom configuration settings (GUCS) for PL/Java, which allows attackers to gain privileges via unspecified vectors.
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Analysis
by VulDB Data Team • 01/25/2023
The vulnerability identified as CVE-2016-0766 represents a critical access control flaw within PostgreSQL database systems that affects multiple version streams including 9.1.x through 9.5.x. This issue specifically targets the handling of Global User Configuration settings within the PL/Java extension, which is a popular Java language procedural language for PostgreSQL databases. The flaw stems from insufficient validation mechanisms that govern how custom configuration parameters are accessed and modified within the database environment, creating potential pathways for unauthorized privilege escalation.
The technical implementation of this vulnerability lies in the improper restriction of access to unspecified custom configuration settings that are managed through the PostgreSQL GUC system. These configuration parameters are typically used to control various aspects of database behavior and extension functionality, particularly within PL/Java which allows Java-based stored procedures and functions to be executed within PostgreSQL. The vulnerability manifests when attackers can manipulate these GUC settings without proper authorization, potentially gaining elevated privileges that should be restricted to database administrators or specific trusted users. This flaw operates at the intersection of database access controls and extension management, where the normal security boundaries between different user roles are bypassed.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass potential full database compromise scenarios. Attackers who successfully exploit this vulnerability could gain access to sensitive database configuration parameters that control extension behavior, potentially enabling them to modify database settings that affect security policies, performance characteristics, or data access controls. The implications are particularly severe in environments where PL/Java is actively used for complex database operations, as the compromised configuration settings could be leveraged to bypass security measures or establish persistent access mechanisms. This vulnerability aligns with CWE-284, which addresses improper access control, and represents a clear violation of the principle of least privilege in database security management.
Organizations utilizing affected PostgreSQL versions should immediately implement mitigations including prompt patching to the latest available versions that address this specific access control flaw. The recommended approach involves upgrading to PostgreSQL 9.1.20 or later, 9.2.15 or later, 9.3.11 or later, 9.4.6 or later, or 9.5.1 or later depending on the specific version in use. Additionally, administrators should conduct thorough security reviews of existing PL/Java configurations, implementing strict access controls for database users who require access to extension management functions. Security monitoring should be enhanced to detect unusual configuration changes or access patterns that might indicate exploitation attempts. The ATT&CK framework categorizes this vulnerability under privilege escalation techniques, specifically targeting the T1068 - Exploitation for Privilege Escalation tactic where attackers leverage software vulnerabilities to gain elevated system access. Organizations should also consider implementing database activity monitoring solutions that can detect anomalous behavior related to GUC parameter modifications and extension configuration changes.