CVE-2007-5956 in Informix Dynamic Server
Summary
by MITRE
Directory traversal vulnerability in IBM Informix Dynamic Server (IDS) before 10.00.xC7W1 allows local users to gain privileges by referencing modified NLS message files through directory traversal sequences in the DBLANG environment variable.
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Analysis
by VulDB Data Team • 11/11/2017
The vulnerability identified as CVE-2007-5956 represents a directory traversal flaw within IBM Informix Dynamic Server version 10.00.xC7W1 and earlier releases. This security weakness specifically affects the handling of National Language Support (NLS) message files during the database server initialization process. The vulnerability stems from insufficient input validation when processing the DBLANG environment variable, which is used to specify the language and locale settings for database operations. When a local user manipulates this environment variable to include directory traversal sequences such as "../" or "..\", the system incorrectly processes these paths, potentially allowing unauthorized access to restricted file system locations.
The technical implementation of this vulnerability occurs during the Informix server startup sequence when it attempts to load NLS message files from locations specified in the DBLANG environment variable. The server performs path resolution without adequate sanitization of the input, enabling attackers to craft malicious paths that bypass normal file access controls. This flaw operates at the file system level where the database server processes user-supplied paths for message file locations, creating an opportunity for privilege escalation. The vulnerability is classified under CWE-22 as a directory traversal attack, which falls under the broader category of path traversal weaknesses that have been consistently identified as critical security flaws in database management systems. The attack vector is particularly concerning because it requires only local system access, making it exploitable by users who already have some level of system presence.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass potential data exposure and system compromise. A local attacker who successfully exploits this vulnerability could gain access to sensitive configuration files, message catalogs, and potentially other system resources that should normally be restricted. This access could enable the attacker to extract database connection information, observe system communications, or modify critical system files that affect database functionality. The vulnerability is particularly dangerous in multi-tenant environments where database servers might be running with elevated privileges, as it could allow an attacker to escalate from a regular user account to a database administrator level. According to ATT&CK framework, this vulnerability maps to T1068 (Exploitation for Privilege Escalation) and T1078 (Valid Accounts) as it leverages existing local access to achieve elevated privileges through improper input handling.
Mitigation strategies for CVE-2007-5956 should focus on both immediate patching and operational hardening measures. The most effective solution involves applying the official IBM security patches that address the directory traversal vulnerability in IDS versions prior to 10.00.xC7W1. Organizations should also implement strict environment variable validation controls to prevent modification of DBLANG settings by unauthorized users. System administrators should regularly audit database server configurations and monitor for unauthorized changes to environment variables that could affect NLS message file resolution. Additionally, implementing least privilege principles for database server processes and restricting local user access to database server components can significantly reduce the attack surface. The vulnerability highlights the importance of input validation in database systems and serves as a reminder of the critical need to maintain up-to-date security patches across all database management system components. Organizations should also consider implementing automated monitoring solutions that can detect anomalous patterns in environment variable usage or file access attempts that might indicate exploitation attempts.