CVE-2005-4740 in DB2 Universal Database
Summary
by MITRE
IBM DB2 Universal Database (UDB) 810 before version 8 FixPak 10 allows remote authenticated users to cause a denial of service (db2jd service crash) by "connecting from a downlevel client."
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Analysis
by VulDB Data Team • 07/07/2021
IBM DB2 Universal Database version 810 before FixPak 10 contains a vulnerability that enables remote authenticated users to trigger a denial of service condition by connecting from a downlevel client. This flaw resides in the db2jd service component which handles client connections and processing. The vulnerability stems from inadequate input validation and connection handling mechanisms within the database server's protocol implementation. When a downlevel client attempts to establish a connection to the database server, the system fails to properly validate the client version information and connection parameters, leading to a service crash that terminates the db2jd process.
The technical implementation of this vulnerability involves the database server's inability to gracefully handle malformed or unsupported client connection requests. According to CWE-20, this represents a classic input validation flaw where the system does not properly sanitize or validate data received from external sources. The downlevel client connection mechanism lacks proper error handling and resource management, causing the db2jd service to encounter unexpected data structures that trigger memory corruption or invalid state transitions. This vulnerability operates at the network protocol level where client-server communication fails to maintain proper state management and validation controls. The flaw is particularly concerning as it requires only authenticated access to exploit, making it accessible to users with legitimate database credentials who may not have malicious intent but inadvertently trigger the condition through improper client usage or connection attempts.
The operational impact of this vulnerability extends beyond simple service disruption as it can compromise database availability and potentially affect business continuity operations. When the db2jd service crashes, all active database connections are terminated, requiring manual intervention to restart the service and potentially causing data loss or transaction rollbacks. Organizations running DB2 UDB version 810 without FixPak 10 are particularly vulnerable to this attack vector, as the service may become unavailable for extended periods while administrators work to restore operations. The vulnerability can be exploited by attackers who gain legitimate database user credentials through other means, making it a significant concern for database security management. According to ATT&CK framework, this vulnerability aligns with T1499.004 which covers network denial of service attacks, and T1566.001 which covers spearphishing via social engineering, as attackers may use legitimate credentials to exploit this weakness.
Mitigation strategies for this vulnerability include applying the official IBM FixPak 10 update which addresses the connection handling and validation issues within the db2jd service. Organizations should also implement network segmentation to limit access to database services and ensure that only authorized clients can establish connections to database servers. Additional defensive measures include monitoring for unusual connection patterns and implementing automated alerting for service crashes or restarts. Database administrators should also review and restrict client connection permissions to minimize the attack surface and ensure that only necessary client versions are allowed to connect to the database server. Regular security assessments and vulnerability scanning should be conducted to identify similar issues within the database infrastructure and ensure that all systems remain up to date with the latest security patches and updates.