CVE-2018-1796 in Informix Dynamic Server Enterprise Edition
Summary
by MITRE
IBM Informix Dynamic Server Enterprise Edition 12.1 could allow a local user to load malicious libraries and gain root privileges. IBM X-Force ID: 149426.
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Analysis
by VulDB Data Team • 11/27/2023
IBM Informix Dynamic Server Enterprise Edition version 12.1 contains a critical local privilege escalation vulnerability that enables authenticated local users to load malicious shared libraries and elevate their privileges to root level access. This vulnerability stems from insufficient privilege validation mechanisms within the server's library loading process, allowing attackers with local account access to manipulate the dynamic linking behavior of the informix service. The flaw specifically affects the server's handling of shared library dependencies during process initialization, where the system fails to properly validate the integrity and origin of dynamically loaded libraries.
The technical exploitation of this vulnerability occurs through a privilege escalation vector that leverages the server's default configuration allowing local users to place malicious shared libraries in directories that are searched during the library loading sequence. When the informix service restarts or reinitializes, it loads these malicious libraries with elevated privileges, effectively granting the local user root access to the system. This type of vulnerability falls under CWE-426 Untrusted Search Path, which specifically addresses the risks associated with insecure library loading mechanisms. The vulnerability is particularly dangerous because it requires minimal attack prerequisites, only local user access and the ability to write to specific directories that are part of the library search path.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it provides attackers with complete system control and access to all data managed by the informix database server. An attacker with root privileges can modify database contents, extract sensitive information, install backdoors, or disable security controls. This vulnerability represents a significant risk to organizations using informix database servers, as it allows attackers to bypass traditional network-based security controls and directly compromise the underlying operating system. The attack vector is particularly concerning from an adversary perspective as it aligns with ATT&CK technique T1068, which covers privilege escalation through local exploits, and T1548.001, covering abuse of elevation tools. The vulnerability affects database servers running on unix-like operating systems where informix is installed with default configurations.
Organizations should immediately apply the vendor-provided security patches and updates to address this vulnerability. System administrators should also implement additional security controls including restricting write permissions to directories in the library search path, implementing file integrity monitoring solutions, and conducting regular security audits of system configurations. The remediation process should include verifying that the informix service runs with minimal required privileges and that the library loading behavior has been hardened against malicious library injection attempts. Additionally, organizations should consider implementing privilege separation mechanisms and monitoring for unusual library loading activities that could indicate exploitation attempts. Regular security assessments should be conducted to identify and remediate similar vulnerabilities in other database systems and applications that may be susceptible to similar privilege escalation attacks through insecure library loading mechanisms.