CVE-2007-4271 in DB2 Universal Database
Summary
by MITRE
Directory traversal vulnerability in IBM DB2 UDB 8 before Fixpak 15 and 9.1 before Fixpak 3 allows local users to create arbitrary files via a .. (dot dot) in an unspecified environment variable, which is appended to "/tmp/" and used as a log file. NOTE: this issue might be related to symlink following.
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Analysis
by VulDB Data Team • 07/24/2019
This vulnerability represents a critical directory traversal flaw in IBM DB2 Universal Database versions 8.0 before Fixpak 15 and 9.1 before Fixpak 3, classified under CWE-22 as improper limitation of a pathname to a restricted directory. The vulnerability occurs when an unspecified environment variable containing user-controllable data is appended to the "/tmp/" directory path and subsequently used as a log file destination. This creates an opportunity for local attackers to manipulate the file system by inserting ".." sequences that can traverse parent directories, potentially allowing arbitrary file creation or modification. The issue specifically manifests when the database engine processes environment variables without proper sanitization or validation of path components, enabling attackers to escape the intended temporary directory scope. The vulnerability is particularly concerning because it operates at the local user level, meaning any user with access to the database environment can exploit this weakness to gain unauthorized file system access.
The technical exploitation mechanism leverages the absence of proper input validation on environment variables that are subsequently used to construct file paths. When the database process handles these variables, it directly concatenates user-supplied input with the "/tmp/" prefix without implementing adequate path validation or normalization. This allows attackers to inject directory traversal sequences that can bypass the intended directory restrictions. The vulnerability is closely related to CWE-36 path traversal and potentially involves symlink following mechanisms as noted in the original description, where attackers might create symbolic links to redirect file operations to unintended locations. The specific use of the "/tmp/" prefix indicates that the vulnerability is particularly dangerous in multi-user environments where temporary file handling is common, as it could allow privilege escalation or data manipulation attacks.
The operational impact of this vulnerability extends beyond simple file system manipulation to potential security breaches and system compromise. Local users could exploit this to create malicious log files in arbitrary locations, potentially leading to privilege escalation if the database process runs with elevated privileges. The vulnerability also poses risks to system integrity, as attackers could overwrite critical system files or create backdoor access points through carefully crafted log file entries. Additionally, the issue affects database audit and logging capabilities, as attackers could manipulate log file destinations to hide malicious activities or redirect logs to locations where they can be easily accessed. This type of vulnerability can also impact compliance requirements and forensic analysis, as log integrity becomes compromised, making it difficult to maintain proper audit trails for security monitoring and incident response activities.
Mitigation strategies for this vulnerability should focus on immediate patch application to the affected IBM DB2 versions, specifically installing Fixpak 15 for version 8.0 and Fixpak 3 for version 9.1. Organizations should also implement proper environment variable validation and sanitization within database configurations to prevent uncontrolled input from being used in path construction operations. The principle of least privilege should be enforced by ensuring database processes run with minimal required permissions and by implementing proper file system access controls. System administrators should conduct thorough security audits of environment variable configurations and monitor for suspicious file creation patterns in temporary directories. Additionally, implementing proper input validation mechanisms and path normalization routines can prevent similar vulnerabilities from occurring in other applications. This vulnerability aligns with ATT&CK technique T1059 for command and script injection and T1070 for indicator removal, as attackers could use this to establish persistence or hide their activities through manipulated log files. Organizations should also consider implementing file integrity monitoring solutions to detect unauthorized file system modifications and maintain proper log file integrity through cryptographic validation mechanisms.