CVE-2010-3433 in PostgreSQL
Summary
by MITRE
The PL/perl and PL/Tcl implementations in PostgreSQL 7.4 before 7.4.30, 8.0 before 8.0.26, 8.1 before 8.1.22, 8.2 before 8.2.18, 8.3 before 8.3.12, 8.4 before 8.4.5, and 9.0 before 9.0.1 do not properly protect script execution by a different SQL user identity within the same session, which allows remote authenticated users to gain privileges via crafted script code in a SECURITY DEFINER function, as demonstrated by (1) redefining standard functions or (2) redefining operators, a different vulnerability than CVE-2010-1168, CVE-2010-1169, CVE-2010-1170, and CVE-2010-1447.
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Analysis
by VulDB Data Team • 09/26/2021
The vulnerability described in CVE-2010-3433 represents a critical privilege escalation issue within PostgreSQL's procedural language implementations, specifically affecting PL/perl and PL/Tcl extensions across multiple version ranges. This flaw exists in the core database engine's handling of script execution contexts when multiple SQL user identities operate within the same database session. The vulnerability stems from insufficient isolation mechanisms that allow authenticated users to manipulate execution environments in ways that can compromise system security. The issue is particularly concerning because it operates at the intersection of database access control and procedural language execution, creating a pathway for unauthorized privilege elevation through carefully crafted code within SECURITY DEFINER functions.
The technical implementation flaw involves the improper handling of user identity context switching within PostgreSQL's procedural language subsystem. When a SECURITY DEFINER function executes, the system should maintain strict isolation between the caller's privileges and the execution environment of the procedural code. However, the vulnerability allows attackers to exploit the session context to redefine standard database functions or operators, effectively bypassing normal access controls. This occurs because the PL/perl and PL/Tcl implementations fail to properly validate or enforce user identity boundaries during script execution, particularly when the same session is used by different SQL users. The vulnerability specifically affects versions where the session management logic did not adequately address cross-user execution scenarios, creating a persistent threat vector that remains active throughout the session lifetime.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass potential data integrity compromise and unauthorized access to database resources. An authenticated attacker with minimal database privileges can leverage this flaw to elevate their access level and potentially gain access to data that should be restricted to higher-privileged users. The ability to redefine standard functions or operators creates a persistent backdoor within the database environment, allowing attackers to manipulate database behavior and potentially access sensitive information. This vulnerability is particularly dangerous in multi-user environments where different users share database sessions or where administrative functions are exposed through procedural language extensions. The attack surface is broadened by the fact that the vulnerability affects multiple PostgreSQL versions simultaneously, indicating a fundamental design flaw rather than a simple coding error.
Mitigation strategies for CVE-2010-3433 should focus on immediate version upgrades to patched PostgreSQL releases, specifically targeting the affected versions mentioned in the vulnerability description. Organizations should implement strict access controls and avoid using SECURITY DEFINER functions when procedural languages are involved, as these functions create the primary attack vector for exploitation. Database administrators should conduct comprehensive audits of existing SECURITY DEFINER functions and evaluate their necessity, particularly those involving PL/perl or PL/Tcl extensions. The implementation of principle of least privilege should be enforced more rigorously, ensuring that database users have only the minimum permissions required for their operations. Additionally, monitoring and logging of procedural language execution should be enhanced to detect anomalous behavior patterns that might indicate exploitation attempts. This vulnerability aligns with CWE-284 (Improper Access Control) and can be mapped to ATT&CK technique T1068 (Exploitation for Privilege Escalation) within the adversary tactics framework, emphasizing the need for comprehensive security controls beyond simple patch management.
The vulnerability demonstrates a classic case of insufficient context isolation in database security mechanisms, where the boundary between different user execution contexts becomes blurred. This flaw represents a fundamental weakness in PostgreSQL's session management architecture that affects the core security model of the database system. Organizations should consider implementing additional security layers such as database activity monitoring, privilege auditing, and regular security assessments to detect and prevent exploitation of similar context switching vulnerabilities. The remediation process should include not only patching the affected versions but also reviewing and strengthening the overall database security posture, particularly focusing on procedural language usage and session management controls.