CVE-2012-2655 in PostgreSQL
Summary
by MITRE
PostgreSQL 8.3.x before 8.3.19, 8.4.x before 8.4.12, 9.0.x before 9.0.8, and 9.1.x before 9.1.4 allows remote authenticated users to cause a denial of service (server crash) by adding the (1) SECURITY DEFINER or (2) SET attributes to a procedural language s call handler.
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Analysis
by VulDB Data Team • 12/06/2021
PostgreSQL versions 8.3.x before 8.3.19, 8.4.x before 8.4.12, 9.0.x before 9.0.8, and 9.1.x before 9.1.4 contain a critical vulnerability that enables authenticated remote attackers to execute a denial of service attack through crafted procedural language call handlers. This vulnerability specifically targets the handling of SECURITY DEFINER and SET attributes within procedural language implementations, creating a condition where legitimate database operations can trigger server crashes. The flaw exists in the database engine's parsing and execution logic for user-defined functions, particularly affecting the internal mechanisms that process these specific attributes during function invocation. This vulnerability represents a classic case of improper input validation and error handling within the database system's procedural language framework. The technical implementation involves the way PostgreSQL processes the security context and configuration settings when executing functions that utilize SECURITY DEFINER or SET clauses, leading to memory corruption or stack overflow conditions that result in complete server termination.
The operational impact of this vulnerability extends beyond simple service disruption, as it affects database availability and integrity within enterprise environments where PostgreSQL serves as a critical data storage layer. Attackers with minimal privileges can exploit this flaw to crash database servers, potentially causing significant downtime for applications dependent on PostgreSQL services. This vulnerability particularly affects systems where users have the ability to create or modify procedural language functions, which is common in development and administrative environments. The attack vector requires only authenticated access to the database system, making it accessible to users with basic database permissions, and the impact is immediate and severe. Organizations running affected PostgreSQL versions face substantial risk of service interruption, especially in production environments where database availability is paramount for business operations. The vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and represents a failure in proper memory management during procedural language execution.
Mitigation strategies for this vulnerability involve immediate patching of affected PostgreSQL installations to the latest stable releases containing the fix. Organizations should prioritize updating their database servers to versions 8.3.19, 8.4.12, 9.0.8, or 9.1.4 respectively, depending on their current version. System administrators should also implement network segmentation and access controls to limit the number of authenticated users who can create or modify procedural language functions. Monitoring should be enhanced to detect unusual patterns in function creation or execution that might indicate exploitation attempts. The fix addresses the underlying issue by implementing proper validation of SECURITY DEFINER and SET attributes during procedural language handler processing, preventing malformed inputs from causing server crashes. From an operational security perspective, this vulnerability demonstrates the importance of maintaining up-to-date database systems and implementing robust access control measures. It also highlights the need for comprehensive vulnerability management programs that can quickly identify and remediate security flaws across database infrastructure. The ATT&CK framework categorizes this vulnerability under privilege escalation and denial of service tactics, emphasizing the need for proper database access controls and the principle of least privilege in database environments. Organizations should conduct thorough testing of patched systems to ensure that the vulnerability remediation does not introduce compatibility issues with existing database applications.