CVE-2009-3471 in DB2
Summary
by MITRE
IBM DB2 8 before FP18, 9.1 before FP8, 9.5 before FP4, and 9.7 before FP2 does not perform the expected drops of certain table functions upon a loss of privileges by the functions definers, which has unspecified impact and remote attack vectors.
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Analysis
by VulDB Data Team • 08/23/2021
IBM DB2 database management systems across multiple versions exhibit a privilege escalation vulnerability that stems from inadequate privilege validation mechanisms during table function operations. This flaw exists in versions prior to specific fix packs including DB2 8.0 before FP18, 9.1 before FP8, 9.5 before FP4, and 9.7 before FP2, representing a significant security gap in database access control. The vulnerability manifests when users lose privileges that were previously granted to define table functions, yet the system fails to properly revoke access to previously created table functions, creating a persistent security exposure.
The technical root cause of this vulnerability lies in the improper handling of privilege revocation within DB2's metadata management system. When a user who originally defined a table function loses the necessary privileges to create such functions, the database engine does not automatically invalidate or drop the existing table function definitions. This creates a scenario where revoked users can continue to access or manipulate table functions they no longer have authorization to use, effectively bypassing the intended access controls. The vulnerability operates at the database engine level where privilege validation occurs during function creation versus function execution phases, creating a temporal window where stale privileges remain active.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass potential data leakage and unauthorized database manipulation. Attackers who can identify this vulnerability can exploit it to maintain access to sensitive table functions even after their privileges have been revoked, potentially enabling them to extract confidential data or perform unauthorized operations within the database. The unspecified impact designation reflects the complexity of determining exactly what data or operations remain accessible, but the remote attack vector capability suggests that this vulnerability can be exploited across network boundaries without requiring local system access. This vulnerability aligns with CWE-284 Access Control Issues, specifically focusing on inadequate privilege checks and improper access control enforcement.
The security implications of CVE-2009-3471 can be mapped to several ATT&CK tactics including privilege escalation and defense evasion. An attacker who successfully exploits this vulnerability can maintain persistent access to database resources through compromised table functions, potentially allowing them to bypass other security controls. The remote nature of the attack vector means that exploitation can occur from external network positions, making it particularly dangerous for database environments accessible over the internet. This vulnerability also relates to the broader category of credential exposure and access control bypass techniques that attackers use to maintain long-term database access.
Organizations should implement immediate mitigations including applying the appropriate fix packs for their DB2 versions, conducting comprehensive privilege audits to identify affected table functions, and implementing additional monitoring for unauthorized access patterns. Database administrators should regularly review and validate user privileges, particularly for database objects that have elevated access requirements. The recommended approach involves not only patching the vulnerability but also establishing more robust privilege management policies that include automatic cleanup of stale database objects when user privileges change. Security monitoring should include detection of anomalous table function usage patterns that could indicate exploitation attempts, and network segmentation should be implemented to limit exposure of database systems to untrusted networks.