CVE-2008-3858 in DB2 Universal Database
Summary
by MITRE
The Downlevel DB2RA Support component in IBM DB2 9.1 before Fixpak 4a allows remote attackers to cause a denial of service (instance crash) via a crafted CONNECT data stream that simulates a V7 client connect request.
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Analysis
by VulDB Data Team • 05/26/2025
The vulnerability identified as CVE-2008-3858 resides within the Downlevel DB2RA Support component of IBM DB2 9.1 prior to Fixpak 4a, representing a significant security flaw that enables remote attackers to execute a denial of service attack against database instances. This weakness specifically targets the handling of CONNECT data streams and exploits a scenario where maliciously crafted data simulates a V7 client connect request, ultimately leading to database instance crashes. The vulnerability operates at the protocol level where the database server fails to properly validate incoming connection requests from older client versions, creating an exploitable condition that can be leveraged by unauthorized actors to disrupt database services.
The technical implementation of this vulnerability stems from inadequate input validation within the Downlevel DB2RA Support component which is designed to maintain backward compatibility with older DB2 client versions. When a malicious CONNECT data stream is received, the system processes the request without proper sanitization of the V7 client simulation parameters, causing the database instance to enter an unstable state and subsequently crash. This flaw represents a classic buffer over-read or improper state handling issue that falls under the CWE-129 weakness category, specifically related to insufficient validation of the length or size of input data. The vulnerability exploits the protocol parsing mechanisms that are intended to support legacy client connections but fail to properly handle malformed or crafted data streams.
The operational impact of this vulnerability extends beyond simple service disruption, as database instance crashes can result in significant business interruption and data availability issues. Organizations relying on IBM DB2 9.1 systems without the appropriate Fixpak 4a update face potential downtime that could affect critical business applications dependent on database connectivity. The remote nature of the attack means that threat actors do not require physical access or local credentials to exploit this weakness, making it particularly dangerous in networked environments. From an attack perspective, this vulnerability aligns with the MITRE ATT&CK framework's privilege escalation and denial of service tactics, where attackers can leverage the weakness to compromise system availability and potentially gain insights into the database infrastructure through the crash patterns.
Mitigation strategies for CVE-2008-3858 primarily focus on applying the official IBM Fixpak 4a update which addresses the input validation flaws in the Downlevel DB2RA Support component. Organizations should also implement network segmentation and access controls to limit exposure of database instances to untrusted networks, while monitoring for unusual connection patterns that might indicate exploitation attempts. Additional defensive measures include configuring firewalls to restrict database port access, implementing intrusion detection systems to monitor for suspicious CONNECT data streams, and establishing robust incident response procedures for handling database instance crashes. The vulnerability highlights the importance of maintaining up-to-date database security patches and demonstrates how legacy compatibility features can introduce security risks when not properly validated against malicious inputs.