CVE-2019-19646 in MySQL Workbench
Summary
by MITRE
pragma.c in SQLite through 3.30.1 mishandles NOT NULL in an integrity_check PRAGMA command in certain cases of generated columns.
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Analysis
by VulDB Data Team • 05/25/2024
The vulnerability identified as CVE-2019-19646 affects SQLite versions through 3.30.1 and resides in the pragma.c file where the integrity_check PRAGMA command fails to properly handle NOT NULL constraints in specific scenarios involving generated columns. This represents a critical flaw in database integrity verification mechanisms that could potentially allow data corruption or unauthorized data access patterns. The issue specifically manifests when SQLite attempts to validate database integrity while processing generated columns that contain NOT NULL constraints, creating a scenario where the integrity check mechanism becomes confused about constraint enforcement.
The technical flaw stems from improper handling of constraint validation within the integrity_check pragma functionality when generated columns are present in the database schema. Generated columns in SQLite are computed values that are automatically maintained by the database engine based on expressions defined during column creation. When these generated columns include NOT NULL constraints, the integrity_check command should verify that all required values are present and valid. However, the flaw in pragma.c causes the system to incorrectly process these constraints, potentially leading to false positive integrity check results or complete failure of the validation process. This vulnerability operates at the core database engine level, affecting how SQLite validates structural integrity and constraint enforcement.
The operational impact of this vulnerability extends beyond simple data validation failures and could compromise database reliability and data integrity across applications that rely on SQLite's integrity_check functionality. Attackers could potentially exploit this weakness to bypass constraint enforcement mechanisms, leading to data inconsistencies or unauthorized data modifications. The vulnerability affects systems where generated columns are used in conjunction with NOT NULL constraints, which is common in applications requiring computed values that must always be present. This could be particularly problematic in financial applications, inventory systems, or any environment where data consistency is critical. The flaw may also enable attackers to manipulate database schemas or force the database engine into unexpected states during integrity verification operations.
Mitigation strategies for CVE-2019-19646 should prioritize upgrading to SQLite version 3.30.2 or later where the vulnerability has been addressed through corrected handling of NOT NULL constraints in integrity_check operations. Organizations should also implement comprehensive database monitoring to detect unusual integrity check behaviors or constraint violations that might indicate exploitation attempts. Database administrators should review existing schemas containing generated columns with NOT NULL constraints and perform manual integrity verification using alternative methods until the upgrade is complete. Security teams should monitor for potential exploitation attempts through database integrity check commands and consider implementing additional access controls around database management operations. This vulnerability aligns with CWE-284, which addresses improper access control in database systems, and may map to ATT&CK techniques related to privilege escalation through database manipulation. The fix implemented by SQLite developers specifically addresses the constraint validation logic in the pragma.c file to ensure proper handling of generated column constraints during integrity verification processes.