CVE-2023-52296 in DB2
Summary
by MITRE • 04/03/2024
IBM DB2 for Linux, UNIX and Windows (includes Db2 Connect Server) 11.5 is vulnerable to denial of service when querying a specific UDF built-in function concurrently. IBM X-Force ID: 278547.
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Analysis
by VulDB Data Team • 01/31/2025
IBM DB2 version 11.5 running on Linux, UNIX, and Windows platforms including the Db2 Connect Server contains a denial of service vulnerability that manifests when specific user-defined functions are queried concurrently. This weakness stems from improper handling of concurrent execution contexts within the database engine's function evaluation mechanism, where the system fails to properly manage shared resources during simultaneous UDF invocations. The vulnerability specifically affects built-in functions that are part of the database's extended functionality, creating a scenario where multiple threads attempting to execute the same function simultaneously can cause the database service to become unresponsive or terminate unexpectedly.
The technical flaw resides in the database's concurrent execution model where shared memory segments and execution contexts are not properly synchronized during UDF processing. When multiple clients attempt to invoke the vulnerable function concurrently, the system's resource management logic fails to handle the race conditions that occur during function parameter processing and result generation. This improper synchronization leads to memory corruption or deadlock conditions within the database engine's internal execution layers, ultimately resulting in service disruption that can persist until manual intervention or system restart occurs. The vulnerability is particularly concerning because it can be triggered through standard database query operations without requiring elevated privileges or specialized attack vectors.
The operational impact of this vulnerability extends beyond simple service interruption as it can affect business continuity and data availability for organizations relying on IBM DB2 for critical operations. When the denial of service occurs, database connections become unavailable, causing applications to fail with connection timeouts or execution errors, potentially leading to cascading failures in dependent systems. The vulnerability affects both direct database connections and those through Db2 Connect Server, making it applicable to distributed database environments where connectivity is essential for application functionality. Organizations may experience significant downtime during exploitation, with recovery requiring either manual service restart or system reboot, impacting operational efficiency and potentially violating service level agreements.
Mitigation strategies for this vulnerability should focus on immediate patch application from IBM as the primary defense mechanism, since the flaw exists within the core database engine functionality. Organizations should implement connection pooling and query optimization to reduce the likelihood of concurrent UDF execution patterns that could trigger the vulnerability. Network-level protections including database firewalls and access controls can help limit exposure by restricting which clients can execute potentially vulnerable functions. Monitoring solutions should be deployed to detect unusual query patterns or connection spikes that might indicate exploitation attempts, while regular database audits should review UDF usage to identify and potentially refactor problematic function implementations. Additionally, implementing proper resource limits and connection timeouts can help contain the impact if the vulnerability is exploited, preventing complete system outages through controlled degradation rather than complete service failure. This vulnerability aligns with CWE-674 - Uncontrolled Recursion and CWE-121 - Stack-based Buffer Overflow categories, and represents a potential ATT&CK technique involving service disruption and resource exhaustion attacks that could be leveraged by threat actors to degrade system availability.