CVE-2017-2246 in Lhaz
Summary
by MITRE
Untrusted search path vulnerability in Installer of Lhaz version 2.4.0 and earlier allows an attacker to gain privileges via a Trojan horse DLL in an unspecified directory.
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Analysis
by VulDB Data Team • 10/26/2019
The vulnerability identified as CVE-2017-2246 represents a critical untrusted search path weakness within the Lhaz installer component version 2.4.0 and earlier. This flaw resides in the installer's dynamic link library loading mechanism, where the application fails to properly validate the source and integrity of dynamically loaded modules. The vulnerability stems from the installer's tendency to search for required DLL files in a predictable sequence of directories without adequate verification of file origins or authenticity. Attackers can exploit this weakness by placing a malicious Trojan horse DLL in an unspecified directory that gets prioritized in the search path, allowing the installer to load and execute the malicious code with elevated privileges. This type of vulnerability aligns with CWE-426, which specifically addresses the execution of untrusted code due to insecure search path handling, and represents a classic privilege escalation vector. The installer's behavior creates a dangerous environment where legitimate system components can be replaced by malicious counterparts simply by manipulating the file system search order.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass broader system compromise capabilities. When an attacker successfully places a malicious DLL in a directory that the installer searches, the malicious code executes with the privileges of the installer process, which typically runs with administrative rights. This creates a pathway for attackers to execute arbitrary code, modify system files, install backdoors, or establish persistent access to the compromised system. The vulnerability is particularly dangerous because it operates at the installation phase, where users may not be actively monitoring the process, and the malicious DLL can be executed without user interaction. From an attacker's perspective, this vulnerability maps to ATT&CK technique T1068, which involves the exploitation of elevated privileges to gain system access, and T1574, which covers hijacking of dynamic link libraries to achieve code execution. The attack surface is further expanded by the fact that this vulnerability can be exploited during legitimate software installation processes, making it harder to detect and defend against.
Mitigation strategies for CVE-2017-2246 must address both the immediate vulnerability and prevent similar issues in future software development. Organizations should immediately update to Lhaz versions that have patched this vulnerability, as the original installer behavior has been corrected in subsequent releases. System administrators should implement strict directory permissions and access controls to prevent unauthorized DLL placement in critical system directories. The principle of least privilege should be enforced by ensuring that installation processes run with minimal required permissions rather than administrative rights. Additionally, implementing application whitelisting policies and using tools like Windows Defender Application Control can prevent execution of unauthorized DLLs. Security professionals should also conduct regular vulnerability assessments to identify other potential search path vulnerabilities in legacy applications and ensure that software development practices follow secure coding guidelines that prevent untrusted search path exploitation. The vulnerability serves as a reminder of the critical importance of proper DLL loading mechanisms and the dangers of insecure path resolution in system installation components, aligning with industry best practices outlined in the OWASP Top Ten and NIST cybersecurity frameworks for preventing privilege escalation attacks.