CVE-2010-3735 in DB2
Summary
by MITRE
The "Query Compiler, Rewrite, Optimizer" component in IBM DB2 UDB 9.5 before FP6a allows remote authenticated users to cause a denial of service (CPU consumption) via a crafted query involving certain UNION ALL views, leading to an indefinitely large amount of compilation time.
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Analysis
by VulDB Data Team • 09/26/2021
The vulnerability identified as CVE-2010-3735 affects IBM DB2 Universal Database version 9.5 before fix pack 6a and resides within the Query Compiler, Rewrite, and Optimizer components. This issue represents a significant denial of service weakness that can be exploited by authenticated remote attackers to consume excessive CPU resources and potentially bring database systems to a halt. The flaw specifically manifests when processing crafted queries that involve certain UNION ALL views, creating a scenario where the database engine enters an inefficient compilation loop that can persist indefinitely.
The technical root cause of this vulnerability stems from inadequate input validation and optimization logic within the query processing pipeline. When a maliciously constructed query containing UNION ALL views is submitted to the database, the optimizer fails to properly detect and terminate recursive compilation processes that can grow exponentially in complexity. This behavior creates a condition where the query compilation phase consumes increasing amounts of CPU cycles without reaching a definitive conclusion, effectively creating a resource exhaustion scenario that can impact system availability. The vulnerability aligns with CWE-400, which catalogs weaknesses related to uncontrolled resource consumption, and represents a classic example of a denial of service attack vector that leverages database query processing logic.
From an operational perspective, this vulnerability poses a substantial risk to database availability and system stability. Remote authenticated users can exploit this weakness to consume excessive CPU resources, potentially causing system performance degradation or complete service unavailability. The impact extends beyond simple resource exhaustion as the indefinite compilation time can affect other database operations and potentially cause cascading failures within the database environment. The vulnerability is particularly concerning because it requires only authenticated access, meaning that legitimate users with appropriate credentials can trigger the denial of service condition, making it difficult to distinguish between legitimate database usage and malicious exploitation.
Organizations affected by this vulnerability should implement immediate mitigations including applying the appropriate IBM fix pack 6a or later releases that contain the necessary patches to address the query compilation logic flaw. Network segmentation and access controls should be reviewed to limit unnecessary authenticated access to database systems where possible. Monitoring should be enhanced to detect unusual CPU consumption patterns and extended query compilation times that may indicate exploitation attempts. Additionally, database administrators should consider implementing query execution time limits and resource allocation controls to prevent individual queries from consuming excessive system resources. The vulnerability demonstrates the importance of proper input validation and resource management in database query processing systems, aligning with ATT&CK technique T1499.004 related to network denial of service attacks and emphasizing the need for robust database security practices.