CVE-2008-3958 in DB2
Summary
by MITRE
IBM DB2 UDB 8 before Fixpak 17 allows remote attackers to cause a denial of service (instance crash) via a crafted CONNECT/ATTACH data stream that simulates a V7 client connect/attach request. NOTE: this may overlap CVE-2008-3858. NOTE: this issue exists because of an incomplete fix for CVE-2008-3959.
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Analysis
by VulDB Data Team • 08/16/2019
IBM DB2 Universal Database version 8 prior to Fixpak 17 contains a critical vulnerability that enables remote attackers to execute denial of service attacks through carefully crafted CONNECT/ATTACH data streams. This vulnerability specifically targets the database server's handling of V7 client connection requests, exploiting an incomplete remediation for a previously identified issue. The flaw manifests when the system receives malformed connection data that simulates a legacy V7 client protocol handshake, causing the database instance to crash and become unavailable to legitimate users. This vulnerability represents a significant operational risk as it allows adversaries to disrupt database services without requiring authentication or elevated privileges, effectively creating a remote attack vector that can be exploited from anywhere on the network.
The technical implementation of this vulnerability resides in the database server's protocol handling layer where it processes incoming connection requests from various client versions. When a maliciously crafted data stream is sent to the DB2 instance, the system attempts to parse the connection parameters and simulate a response appropriate for a V7 client, but fails to properly validate or handle the malformed input. This processing error triggers an unhandled exception within the database engine's connection management module, resulting in an abrupt termination of the database instance. The incomplete fix for CVE-2008-3959, which was supposed to address similar connection handling issues, left critical validation gaps that allow this specific attack pattern to succeed. This vulnerability is categorized under CWE-129 Input Validation and CWE-20 Improper Input Validation, as it fails to properly validate incoming connection data streams.
The operational impact of this vulnerability extends beyond simple service disruption, as database availability is fundamental to business operations across virtually all enterprise environments. When an attacker successfully exploits this vulnerability, they can cause cascading failures that affect dependent applications, potentially leading to data loss, financial impact, and reputational damage. The remote nature of the attack means that adversaries can target vulnerable systems from outside the organization's network perimeter, making traditional network security controls less effective. Organizations that rely heavily on DB2 for mission-critical applications face particularly high risk, as the denial of service can affect multiple concurrent users and applications simultaneously. The vulnerability also creates opportunities for attackers to use this as a stepping stone for further exploitation, as database downtime often creates windows for additional attacks or reconnaissance activities.
Organizations should immediately implement the available IBM Fixpak 17 update to address this vulnerability, as it contains the comprehensive fix for the incomplete remediation of CVE-2008-3959. Network segmentation and firewall rules should be implemented to restrict access to DB2 instances, particularly limiting connections to trusted IP addresses and blocking unnecessary ports. Monitoring should be enhanced to detect unusual connection patterns or malformed data streams that might indicate exploitation attempts. System administrators should also consider implementing intrusion detection systems that can identify and alert on suspicious connection attempts matching the attack pattern described in this vulnerability. The ATT&CK framework categorizes this as a Denial of Service attack technique, specifically targeting database services through protocol manipulation, and organizations should include this vulnerability in their threat modeling exercises to understand potential attack vectors and impact scenarios.