CVE-2018-16850 in PostgreSQL
Summary
by MITRE • 01/25/2023
postgresql before versions 11.1, 10.6 is vulnerable to a to SQL injection in pg_upgrade and pg_dump via CREATE TRIGGER ... REFERENCING. Using a purpose-crafted trigger definition, an attacker can cause arbitrary SQL statements to run, with superuser privileges.
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Analysis
by VulDB Data Team • 06/06/2023
The vulnerability identified as CVE-2018-16850 represents a critical SQL injection flaw in PostgreSQL database systems affecting versions prior to 11.1 and 10.6. This security weakness specifically targets the pg_upgrade and pg_dump utilities, which are essential tools for database migration and backup operations. The vulnerability stems from improper handling of trigger definitions during database upgrade processes, creating an avenue for malicious actors to execute unauthorized SQL commands with elevated privileges. The flaw exists within the REFERENCING clause of CREATE TRIGGER statements, where user-supplied input is not adequately sanitized or escaped before being incorporated into database operations.
The technical exploitation of this vulnerability occurs through crafted trigger definitions that manipulate the REFERENCING clause to inject malicious SQL payloads. When PostgreSQL processes these malformed trigger definitions during pg_upgrade or pg_dump operations, the system fails to properly validate or escape the input parameters, allowing attackers to inject arbitrary SQL commands that execute with superuser privileges. This presents a severe privilege escalation risk since the injected commands run with the highest possible database permissions, potentially enabling complete database compromise, data exfiltration, or unauthorized access to sensitive information. The vulnerability operates at the database engine level, making it particularly dangerous as it bypasses typical application-level security controls and can affect the underlying database infrastructure directly.
The operational impact of this vulnerability extends beyond immediate database compromise to encompass broader organizational security risks. Attackers leveraging this flaw can perform unauthorized data manipulation, execute destructive operations, or establish persistent access points within database environments. The vulnerability is particularly concerning for organizations relying on automated database upgrade processes, as it can be exploited during routine maintenance operations without detection. Security teams face significant challenges in identifying and mitigating this threat since it operates within legitimate database administration tools, making malicious activity appear as normal administrative operations. The potential for data loss, unauthorized access, and system compromise creates substantial business continuity risks for organizations dependent on PostgreSQL databases.
Organizations should immediately implement mitigation strategies including upgrading to PostgreSQL versions 11.1 or 10.6, which contain the necessary patches to address this vulnerability. System administrators should also review and restrict access to pg_upgrade and pg_dump utilities, ensuring that only authorized personnel can execute these operations. Input validation and sanitization measures should be strengthened for all database administration tools, particularly those handling trigger definitions and schema modifications. Network segmentation and monitoring solutions should be enhanced to detect unusual database activity patterns that might indicate exploitation attempts. Additionally, security teams should conduct comprehensive vulnerability assessments to identify any potential exploitation attempts and implement proper access controls for database administrative functions. This vulnerability aligns with CWE-89, representing a classic SQL injection weakness, and maps to ATT&CK technique T1078 for valid accounts and T1499 for endpoint disruption, highlighting the multi-faceted nature of the threat posed by this vulnerability.