CVE-2011-1846 in DB2
Summary
by MITRE
IBM DB2 9.5 before FP7 and 9.7 before FP4 on Linux, UNIX, and Windows does not properly revoke role membership from groups, which allows remote authenticated users to execute non-DDL statements by leveraging previous inherited possession of a role, a different vulnerability than CVE-2011-0757. NOTE: some of these details are obtained from third party information.
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Analysis
by VulDB Data Team • 11/05/2021
IBM DB2 database management system versions 9.5 before fix pack 7 and 9.7 before fix pack 4 contain a privilege escalation vulnerability in their role-based access control implementation. This flaw exists in the group membership revocation mechanism where the system fails to properly invalidate role memberships when group memberships change. The vulnerability specifically affects Linux, UNIX, and Windows platforms, creating a persistent security weakness that can be exploited by authenticated attackers. The issue manifests when users previously possessed roles through group membership but those group memberships have since been revoked or modified, yet the system continues to honor the inherited role privileges.
The technical flaw stems from improper handling of role inheritance and group membership transitions within the database's access control subsystem. When a user belongs to a group that has been granted specific database roles, the system should automatically revoke those role privileges when the group membership is terminated. However, IBM DB2 fails to properly clean up these inherited permissions, allowing attackers to maintain access to database resources that should no longer be available to them. This represents a classic privilege escalation vulnerability where legitimate users can leverage their previous access rights to perform unauthorized operations, though the vulnerability specifically allows execution of non-DDL statements, indicating the attacker can perform data manipulation and retrieval operations while being restricted from structural database changes.
The operational impact of this vulnerability is significant as it enables authenticated attackers to maintain unauthorized access to database resources beyond their intended scope. Attackers who previously had access through group membership can continue to execute queries, modify data, and perform other database operations that they should no longer have access to. This creates a persistent backdoor that could be exploited for data exfiltration, data manipulation, or further reconnaissance within the database environment. The vulnerability's classification as a privilege escalation issue means that even users with limited database access could potentially gain broader privileges through this mechanism, making it particularly dangerous in environments where database administrators carefully control access rights.
Security professionals should note that this vulnerability differs from CVE-2011-0757, indicating it represents a distinct issue in the database's access control implementation. The problem aligns with CWE-284 Access Control Issues, specifically concerning improper privilege management and role-based access control failures. From an ATT&CK framework perspective, this vulnerability maps to privilege escalation techniques where adversaries leverage inherited permissions to maintain access beyond their intended scope. Organizations should immediately apply the relevant fix packs for IBM DB2 9.5 FP7 and 9.7 FP4 to resolve this issue, as the vulnerability allows persistent unauthorized access that could lead to data compromise. Additionally, implementing regular access reviews and monitoring for unusual database activity can help detect exploitation attempts before they result in significant damage to the database environment.