CVE-2011-1847 in DB2
Summary
by MITRE
IBM DB2 9.5 before FP7 and 9.7 before FP4 on Linux, UNIX, and Windows does not properly enforce privilege requirements for table access, which allows remote authenticated users to modify SYSSTAT.TABLES statistics columns via an UPDATE statement. 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 that stems from improper enforcement of access controls for system tables. This vulnerability specifically affects the SYSSTAT.TABLES statistics columns and allows authenticated remote attackers to modify these critical system statistics through carefully crafted UPDATE statements. The flaw represents a significant security weakness in the database's authorization model, as it permits unauthorized modification of system metadata that should be protected from user manipulation. This issue impacts installations running on Linux, UNIX, and Windows operating systems, making it broadly applicable across enterprise database environments. The vulnerability falls under the CWE-284 category of Improper Access Control, which specifically addresses insufficient privileges or access control mechanisms that allow unauthorized access to system resources.
The technical exploitation of this vulnerability occurs when an authenticated user with minimal privileges attempts to execute an UPDATE statement against the SYSSTAT.TABLES system table. This table contains critical statistical information about database objects that is typically used for performance monitoring and query optimization purposes. The improper privilege enforcement means that users who should not have write access to these system statistics can manipulate the data, potentially leading to incorrect performance metrics, altered query execution plans, or even data integrity issues. Attackers can leverage this to either corrupt system statistics that affect database performance or to gain insights into the database structure that would otherwise be protected. The vulnerability demonstrates a fundamental flaw in the database's security model where system table access controls are insufficient to prevent unauthorized modifications.
The operational impact of this vulnerability extends beyond simple data corruption, as it can significantly affect database performance and reliability. When system statistics are modified, the database query optimizer may make incorrect decisions based on false information, leading to suboptimal query execution plans that degrade overall system performance. Additionally, the integrity of database monitoring and maintenance operations becomes compromised since the statistics used for these purposes are now potentially manipulated by unauthorized users. This vulnerability can also serve as a stepping stone for more sophisticated attacks, as attackers might use the modified statistics to identify other system weaknesses or to mask their activities within the database environment. The remote nature of the attack means that exploitation does not require physical access to the system, making it particularly dangerous in networked environments.
Organizations affected by this vulnerability should immediately apply the relevant fix packs to upgrade their IBM DB2 installations to versions that properly enforce privilege requirements for system table access. The recommended mitigation involves applying IBM fix pack 7 for DB2 9.5 and fix pack 4 for DB2 9.7, which contain the necessary security patches to address the improper access control mechanism. System administrators should also conduct thorough security assessments of their database environments to identify any potential unauthorized modifications that may have already occurred. Monitoring and auditing of database activities should be enhanced to detect unusual UPDATE operations against system tables, as this could indicate exploitation attempts. From an ATT&CK framework perspective, this vulnerability maps to privilege escalation techniques and defense evasion strategies, as it allows attackers to modify system data without detection while potentially gaining deeper insights into the database infrastructure. Organizations should also review their database user permissions and access controls to ensure that only authorized personnel have the necessary privileges to interact with system tables.