CVE-2017-2189 in RW-4040 Driver Installer
Summary
by MITRE
Untrusted search path vulnerability in RW-4040 driver installer for Windows 7 version 2.27 allows an attacker to gain privileges via a Trojan horse DLL in an unspecified directory.
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Analysis
by VulDB Data Team • 10/16/2019
The CVE-2017-2189 vulnerability represents a critical untrusted search path weakness in the RW-4040 driver installer for Windows 7 version 2.27, classified under CWE-427 Untrusted Search Path. This flaw resides in the installer's failure to properly validate or sanitize the dynamic link library search order, creating an avenue for privilege escalation attacks. The vulnerability manifests when the installer processes a Trojan horse DLL located in an unspecified directory, allowing malicious code execution with elevated privileges. This type of vulnerability falls squarely within the ATT&CK technique T1068 Exploitation for Privilege Escalation, as it leverages installer weaknesses to achieve higher system access levels.
The technical implementation of this vulnerability stems from improper handling of the Windows DLL search mechanism, where the installer does not enforce a secure search path policy. When the RW-4040 driver installer executes, it follows a predictable search sequence that includes the current working directory and other insecure locations before checking the system directories. Attackers can exploit this by placing a malicious DLL with the same name as a legitimate library the installer expects to load, causing the system to execute the attacker-controlled code instead of the intended library. This behavior directly violates security principles of least privilege and secure coding practices, as the installer lacks proper input validation and path sanitization measures.
The operational impact of CVE-2017-2189 extends beyond simple privilege escalation, as it provides attackers with a persistent foothold in compromised systems. Once executed, the malicious DLL can establish backdoors, harvest credentials, or deploy additional malware components, making this vulnerability particularly dangerous in enterprise environments. The vulnerability affects Windows 7 systems specifically, though similar issues may exist in other operating system versions that exhibit comparable insecure search path behaviors. The lack of specific directory information in the original description suggests that attackers could potentially place malicious DLLs in multiple locations, including the user's working directory or other insecure paths accessible to the installer process.
Mitigation strategies for CVE-2017-2189 should focus on implementing proper secure coding practices and system hardening measures. Organizations should ensure that all installer applications enforce a secure search path by explicitly specifying full paths to required libraries and avoiding reliance on the default Windows DLL search order. The recommended approach includes implementing the ATT&CK technique T1554 Compromise Client Software Binaries to prevent unauthorized modifications to legitimate installer components. System administrators should also apply the principle of least privilege by running installers with minimal necessary permissions and implementing application whitelisting policies to restrict execution of unauthorized DLLs. Additionally, regular security assessments should verify that all third-party installers follow secure coding practices and that system directories maintain proper access controls to prevent unauthorized DLL placement.