CVE-2007-4270 in DB2 Universal Database
Summary
by MITRE
Multiple race conditions in IBM DB2 UDB 8 before Fixpak 15 and 9.1 before Fixpak 3 allow local users to gain root privileges via a symlink attack on certain files.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 07/24/2019
The vulnerability identified as CVE-2007-4270 represents a critical security flaw in IBM DB2 Universal Database versions 8 prior to Fixpak 15 and version 9.1 prior to Fixpak 3. This issue stems from multiple race conditions that occur during the handling of symbolic links within the database system's file operations. The vulnerability specifically affects local users who can exploit these timing discrepancies to escalate their privileges to root level access. The race conditions manifest when the system processes certain files that are subject to symbolic link manipulation during database operations, creating opportunities for malicious actors to intercept and manipulate file access sequences. Such vulnerabilities are particularly dangerous because they allow privilege escalation from local user accounts to the highest system privileges, effectively compromising the entire database server environment.
The technical implementation of this vulnerability involves the exploitation of time-of-check to time-of-use (TOCTOU) race conditions in the database's file handling mechanisms. When DB2 processes certain files during normal operations, it performs checks to determine file properties and permissions before actually using those files. The race condition occurs because there is a window between when the system checks file attributes and when it actually operates on the file, during which a malicious user can replace the original file with a symbolic link pointing to a different location. This allows the attacker to manipulate the system into executing code with elevated privileges or accessing files that should normally be restricted. The vulnerability is classified under CWE-367 which specifically addresses Time-of-Check to Time-of-Use race conditions, making it a well-documented pattern of security flaws in Unix-like systems. The attack vector requires local access to the system, but the privilege escalation potential makes it particularly severe.
The operational impact of this vulnerability extends far beyond simple local privilege escalation, as it can lead to complete system compromise and data breaches. Once an attacker gains root privileges through this exploit, they can modify database files, access sensitive information, install backdoors, or manipulate database configurations to maintain persistent access. The vulnerability affects database administrators and system operators who may not be fully aware of the risks associated with local users having access to systems running vulnerable DB2 versions. From an ATT&CK framework perspective, this vulnerability maps to privilege escalation techniques and can be leveraged to achieve initial access or maintain persistence within a network environment. The attack can be particularly insidious because it may not immediately trigger alerts or log entries that would normally indicate malicious activity, as the legitimate database processes are being used to execute the exploit.
Mitigation strategies for CVE-2007-4270 focus primarily on applying the appropriate IBM security patches and fixpaks that address the race conditions in DB2's file handling processes. Organizations should immediately upgrade to IBM DB2 UDB 8 Fixpak 15 or later, and version 9.1 Fixpak 3 or later to resolve the vulnerability. System administrators should also implement proper file access controls and monitor for unauthorized symbolic link creation in database directories. Additional protective measures include disabling unnecessary database services, implementing robust access controls, and ensuring that database files are not writable by non-privileged users. The vulnerability highlights the importance of maintaining current security patches and conducting regular vulnerability assessments to identify and remediate similar race condition issues in database systems. Organizations should also consider implementing monitoring solutions that can detect unusual file access patterns or privilege escalation attempts that may indicate exploitation of similar vulnerabilities.