CVE-2018-1888 in i Access
Summary
by MITRE
An untrusted search path vulnerability in IBM i Access for Windows versions 7.1 and earlier on Windows can allow arbitrary code execution via a Trojan horse DLL in the current working directory, related to use of the LoadLibrary function. IBM X-Force ID: 152079.
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Analysis
by VulDB Data Team • 06/23/2023
The vulnerability identified as CVE-2018-1888 represents a critical untrusted search path flaw in IBM i Access for Windows versions 7.1 and earlier, presenting a significant security risk that can be exploited to achieve arbitrary code execution. This vulnerability specifically affects the Windows operating system environment where IBM i Access software is installed, creating a dangerous attack vector that leverages the inherent trust placed in system paths during dynamic library loading operations. The flaw manifests when the application employs the LoadLibrary function without proper validation of the library search path, allowing attackers to place malicious DLL files in the current working directory and have them loaded automatically by the vulnerable application.
The technical nature of this vulnerability aligns with CWE-426, which describes untrusted search path vulnerabilities where applications search for libraries in insecure locations. When IBM i Access for Windows executes and encounters a missing dependency, it follows the standard Windows DLL search order which includes the current working directory before checking system directories. This behavior creates an opportunity for attackers to position a malicious DLL with the same name as a legitimate library that the application expects to load, thereby executing arbitrary code with the privileges of the user running the vulnerable application. The vulnerability is particularly dangerous because it requires no special privileges to exploit and can be triggered through social engineering or by manipulating the application's working directory.
The operational impact of this vulnerability extends beyond simple code execution, as it can enable attackers to escalate privileges, access sensitive data, or establish persistent access to systems running vulnerable versions of IBM i Access. Attackers can leverage this vulnerability to perform various malicious activities including data exfiltration, system reconnaissance, or deploying additional malware. The attack surface is broad since any user who runs the vulnerable IBM i Access application can be targeted, making this a particularly concerning vulnerability for enterprise environments where multiple users may have access to these applications. Organizations using IBM i Access for Windows in their infrastructure face significant risk if they have not patched to versions 7.2 or later, as the vulnerability remains exploitable in older releases.
Mitigation strategies for CVE-2018-1888 should prioritize immediate patching of affected systems to IBM i Access for Windows versions 7.2 and later, which contain the necessary security fixes to address the untrusted search path vulnerability. System administrators should also implement proper application whitelisting policies to prevent unauthorized DLL files from executing in the current working directory of critical applications. Additional protective measures include configuring the Windows environment to use secure DLL search paths through the SetDllDirectory function or by modifying the system PATH variable to prioritize system directories over user directories. Organizations should also conduct thorough security assessments to identify all instances of vulnerable software within their environment and implement network segmentation to limit the potential impact of successful exploitation attempts. The vulnerability demonstrates the importance of following secure coding practices and adheres to ATT&CK technique T1059.001 for command and scripting interpreter, as attackers can leverage this vulnerability to execute malicious code through legitimate system processes.