CVE-2017-2249 in Lhaz+
Summary
by MITRE
Untrusted search path vulnerability in Self-extracting archive files created by Lhaz+ version 3.4.0 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-2017-2249 represents a critical untrusted search path weakness within Lhaz+ software version 3.4.0 and earlier, specifically affecting self-extracting archive files. This flaw stems from improper handling of dynamic library loading sequences where the application fails to validate the source and integrity of loaded modules. The vulnerability creates a pathway for privilege escalation attacks through the exploitation of Trojan horse DLL files placed in unspecified directories that are searched before system-protected locations. The root cause aligns with CWE-427, which addresses uncontrolled search path dependencies, and CWE-428, covering untrusted search path vulnerabilities. Attackers can leverage this weakness by placing malicious DLL files in directories that are prioritized in the search order, enabling code execution with elevated privileges when the vulnerable application processes self-extracting archives.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass potential system compromise and data exfiltration capabilities. When a user executes a self-extracting archive created with Lhaz+ versions affected by this vulnerability, the application's dynamic linking mechanism searches through a predetermined path sequence that includes user-writable directories. This behavior violates fundamental security principles of least privilege and secure coding practices, creating a persistent attack vector that can be exploited across multiple system contexts. The vulnerability's exploitation requires minimal user interaction, typically involving the execution of a maliciously crafted archive file, making it particularly dangerous in environments where users have the ability to execute arbitrary code or where automated execution mechanisms exist. This weakness directly maps to ATT&CK technique T1059, which covers command and scripting interpreter usage, and T1068, covering privilege escalation through local exploitation.
Mitigation strategies for CVE-2017-2249 require immediate patching of affected Lhaz+ versions to address the untrusted search path implementation. Organizations should implement application whitelisting policies to restrict execution of unauthorized binaries and establish secure coding practices that enforce absolute path resolution for dynamic library loading. System administrators should conduct comprehensive vulnerability assessments to identify all instances of Lhaz+ versions prior to 3.4.1 and ensure proper patch management procedures are in place. Additionally, the implementation of security controls such as Windows Defender Application Control or similar endpoint protection mechanisms can help prevent execution of malicious DLLs in privileged contexts. Regular security audits should verify that applications properly implement secure search path mechanisms and that dynamic library loading operations adhere to security best practices established in industry standards such as the OWASP Secure Coding Practices and NIST SP 800-160 guidelines. The vulnerability demonstrates the critical importance of validating library search paths and implementing proper privilege separation in software development processes to prevent similar issues in future releases.