CVE-2018-1633 in Informix Dynamic Server Enterprise Edition
Summary
by MITRE
IBM Informix Dynamic Server Enterprise Edition 12.1 could allow a local user logged in with database administrator user to gain root privileges through a symbolic link vulnerability in onsrvapd. IBM X-Force ID: 144434.
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Analysis
by VulDB Data Team • 11/27/2023
The vulnerability identified as CVE-2018-1633 affects IBM Informix Dynamic Server Enterprise Edition version 12.1 and represents a critical privilege escalation flaw that enables local database administrators to escalate their privileges to root level access. This security weakness resides within the onsrvapd component of the Informix server, which is responsible for managing server processes and maintaining system integrity. The vulnerability specifically manifests through a symbolic link manipulation issue that allows authenticated users with database administrator privileges to exploit a flaw in the permission handling mechanisms of the system.
The technical implementation of this vulnerability involves a race condition or improper handling of symbolic links within the onsrvapd service. When a database administrator executes certain operations, the system creates or modifies symbolic links without proper validation of the target paths or adequate permission checks. This flaw allows the malicious user to manipulate the symbolic link structure to point to critical system files or directories, effectively bypassing normal access controls and gaining elevated privileges. The vulnerability is particularly dangerous because it leverages the trust relationship between the database administrator account and the underlying operating system, enabling lateral movement and system compromise.
The operational impact of CVE-2018-1633 extends beyond simple privilege escalation to encompass full system compromise and potential data exfiltration. Once an attacker escalates to root privileges, they can modify system files, install persistent backdoors, access all user accounts, and manipulate database contents without detection. This vulnerability directly violates the principle of least privilege and can lead to complete system takeover, especially in environments where database administrators have broad access rights. The attack vector requires only local access with database administrator credentials, making it particularly dangerous in multi-tenant environments or systems where database access is more permissive than necessary.
Security professionals should consider this vulnerability in the context of the CWE-264 weakness category, which encompasses permissions, privileges, and access control issues. The flaw aligns with ATT&CK technique T1068, which covers "Exploitation for Privilege Escalation" and demonstrates how attackers can leverage existing access to gain higher system privileges. Organizations should implement immediate mitigations including applying the vendor-provided patches, restricting database administrator access to only necessary system resources, and monitoring for suspicious symbolic link creation patterns. Additionally, system administrators should consider implementing mandatory access controls and privilege separation mechanisms to limit the potential impact of such vulnerabilities, while also conducting regular security assessments to identify similar privilege escalation vectors within their database environments.