CVE-2023-40372 in DB2
Summary
by MITRE • 10/25/2023
IBM Db2 for Linux, UNIX and Windows (includes Db2 Connect Server) 11.5 is vulnerable to denial of service with a specially crafted SQL statement using External Tables. IBM X-Force ID: 263499.
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Analysis
by VulDB Data Team • 11/03/2023
The vulnerability identified as CVE-2023-40372 affects IBM Db2 for Linux, UNIX and Windows versions including Db2 Connect Server 11.5, representing a critical denial of service weakness that can be exploited through carefully constructed SQL statements utilizing External Tables functionality. This vulnerability falls under the broader category of software flaws that can compromise system availability and operational continuity within database environments. The issue specifically targets the processing of external table references within SQL queries, where malformed or maliciously crafted statements can trigger unexpected behavior in the database engine's execution path. According to industry standards, this vulnerability aligns with CWE-400, which categorizes denial of service conditions that arise from uncontrolled resource consumption or improper handling of input data within software systems. The attack vector leverages the external table feature that allows Db2 to interface with external data sources, creating a potential pathway for adversaries to disrupt database operations through carefully crafted SQL syntax.
The technical flaw manifests when the Db2 database engine processes SQL statements containing external table references that include malformed parameters or unexpected data structures. During the parsing and execution phase of these statements, the database engine encounters conditions that cause it to enter an unrecoverable state or consume excessive system resources, ultimately leading to service disruption. The vulnerability exploits the way Db2 handles external table metadata and data access patterns, particularly when the external table definition references non-existent or improperly formatted data sources. This weakness can be triggered through various SQL constructs including but not limited to CREATE TABLE statements with external table specifications, SELECT queries referencing external tables, or other operations that require the database to validate or access external data sources. The exploitation mechanism typically requires minimal privileges and can be executed by authenticated users who have access to the database system, making it particularly concerning for environments where database access controls may be insufficient.
The operational impact of CVE-2023-40372 extends beyond simple service interruption to potentially compromise business continuity and data availability within affected systems. Organizations running IBM Db2 11.5 deployments face significant risk of unauthorized service disruption that can affect critical business applications relying on database operations. The vulnerability can be exploited to cause database processes to crash, hang, or consume excessive memory and CPU resources, effectively rendering database services unavailable to legitimate users. This denial of service condition can persist until manual intervention occurs, including database restarts, process termination, or system reboot operations that may result in data loss or extended downtime. The attack can be particularly damaging in production environments where database availability is mission-critical, as it may require immediate incident response procedures and potentially impact downstream applications that depend on the affected database services. According to ATT&CK framework, this vulnerability represents a denial of service technique that can be classified under T1499.004, which covers network denial of service attacks through resource exhaustion or system instability.
Organizations affected by this vulnerability should implement immediate mitigations including applying the latest IBM security patches and updates that address the specific flaw in external table processing. System administrators should also consider implementing network segmentation and access controls to limit exposure to the vulnerability, particularly by restricting SQL statement execution privileges to trusted users only. Database monitoring should be enhanced to detect unusual resource consumption patterns or abnormal SQL statement processing that might indicate exploitation attempts. Additionally, organizations should develop incident response procedures that include immediate containment strategies for database service disruptions, including automated alerting systems that can detect when database processes become unresponsive or consume excessive resources. The implementation of SQL statement auditing and validation mechanisms can help identify potentially malicious SQL constructs before they can be executed against the database system. Regular security assessments and vulnerability scanning should be conducted to ensure comprehensive protection against similar issues, while maintaining awareness of related vulnerabilities within the IBM Db2 ecosystem that may present additional attack vectors requiring coordinated mitigation strategies.