CVE-2018-1636 in Informix Dynamic Server Enterprise Edition
Summary
by MITRE
Stack-based buffer overflow in oninit in IBM Informix Dynamic Server Enterprise Edition 12.1 allows an authenticated user to execute predefined code with root privileges, such as escalating to a root shell. IBM X-Force ID: 144441.
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Analysis
by VulDB Data Team • 11/27/2023
The vulnerability identified as CVE-2018-1636 represents a critical stack-based buffer overflow flaw within the oninit component of IBM Informix Dynamic Server Enterprise Edition version 12.1. This issue affects the database management system's initialization process where the oninit utility handles system startup operations. The vulnerability specifically manifests during the execution of the oninit utility which is responsible for initializing the Informix database server environment and managing system resources during startup procedures.
The technical implementation of this buffer overflow occurs when the oninit utility processes certain input parameters or configuration values without proper bounds checking on stack-allocated memory buffers. This flaw enables an authenticated user with sufficient privileges to manipulate the input data in such a way that memory corruption occurs within the stack space. The vulnerability is particularly dangerous because it operates during the system initialization phase when the process typically runs with elevated privileges, creating a pathway for privilege escalation attacks. The stack-based nature of the overflow means that the attacker can overwrite return addresses and function pointers on the call stack, potentially redirecting program execution flow to malicious code.
The operational impact of this vulnerability is severe as it allows authenticated users to execute arbitrary code with root privileges, effectively providing complete system compromise capabilities. An attacker who can authenticate to the Informix server can leverage this vulnerability to escalate their privileges from a regular database user to root level access, enabling them to execute commands with system-level privileges. This privilege escalation capability allows attackers to gain full control over the database server, potentially leading to data exfiltration, system modification, or further network penetration. The vulnerability particularly affects enterprise environments where database administrators may have elevated access rights and where the database server operates with root privileges during initialization.
Mitigation strategies for this vulnerability should focus on immediate patch application from IBM as the primary defense mechanism, given that this is a known issue with available vendor fixes. Organizations should implement strict access controls limiting authentication privileges to only necessary personnel and ensure that the oninit utility runs with the minimum required privileges rather than root access. Network segmentation and monitoring should be enhanced to detect unusual authentication patterns or attempts to execute initialization utilities with elevated privileges. The vulnerability aligns with CWE-121 Stack-based Buffer Overflow, which is classified under the Common Weakness Enumeration framework as a fundamental programming error that occurs when data is copied into a stack buffer without proper bounds checking. From an adversarial perspective, this vulnerability maps to ATT&CK technique T1068, which involves exploiting legitimate credentials and privilege escalation to gain system-level access, demonstrating how authenticated access can be leveraged to achieve unauthorized system control. Organizations should also consider implementing runtime protection mechanisms and regular security assessments to identify potential exploitation attempts.