CVE-2015-9268 in Scriptable Install System
Summary
by MITRE
Nullsoft Scriptable Install System (NSIS) before 2.49 has unsafe implicit linking against Version.dll. In other words, there is no protection mechanism in which a wrapper function resolves the dependency at an appropriate time during runtime.
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Analysis
by VulDB Data Team • 05/19/2023
The vulnerability identified as CVE-2015-9268 affects Nullsoft Scriptable Install System (NSIS) versions prior to 2.49, presenting a significant security risk through unsafe implicit linking practices. This issue resides in the installer framework's dynamic linking mechanism where the system fails to properly resolve dependencies at runtime, creating opportunities for malicious code injection and privilege escalation attacks. The flaw specifically manifests in how NSIS handles Version.dll dependencies, which are critical for version information retrieval during installation processes. This vulnerability represents a classic example of improper dynamic linking that can be exploited by attackers to manipulate the installation process and potentially execute arbitrary code with elevated privileges.
The technical root cause of this vulnerability stems from the absence of proper dependency resolution mechanisms within NSIS's runtime environment. When NSIS attempts to load Version.dll, it relies on implicit linking rather than explicit linking, which means the system searches for the required DLL in the system's PATH without verifying the authenticity or integrity of the loaded module. This approach creates a window of opportunity for attackers to place malicious versions of Version.dll in strategic locations within the system PATH, allowing them to intercept and manipulate the installation process. The vulnerability is classified under CWE-1139 which specifically addresses improper linking and dependency resolution issues in software components. This weakness directly enables attackers to perform DLL hijacking attacks, where malicious libraries are loaded instead of legitimate ones during the installation process.
The operational impact of CVE-2015-9268 extends beyond simple privilege escalation, as it can be leveraged to compromise entire installation environments and potentially establish persistent backdoors within target systems. Attackers can exploit this vulnerability by crafting malicious installers that manipulate the loading sequence of Version.dll, thereby gaining control over the installation process and potentially executing arbitrary code with system-level privileges. The vulnerability affects organizations that rely on NSIS for software deployment, making it particularly dangerous in enterprise environments where automated installation processes are common. This weakness can be exploited through social engineering attacks where users unknowingly execute malicious installers, or through supply chain attacks where legitimate installers are compromised. The attack vector aligns with ATT&CK technique T1059.001 for command and scripting interpreter and T1547.001 for registry run keys, as the exploitation can lead to persistence mechanisms being established during installation. Organizations using vulnerable versions of NSIS are at risk of having their software deployment processes compromised, potentially leading to data breaches, system compromise, or unauthorized access to sensitive environments.
Mitigation strategies for CVE-2015-9268 primarily focus on upgrading to NSIS version 2.49 or later, which includes proper dependency resolution mechanisms and explicit linking practices. System administrators should implement strict PATH management controls and monitor for unauthorized DLL placements in system directories. The implementation of application whitelisting solutions can prevent execution of unauthorized DLLs, while regular security audits of installation packages can identify potentially compromised components. Organizations should also consider implementing runtime protection mechanisms that monitor for suspicious DLL loading patterns and enforce proper module authentication. Additionally, security awareness training for developers working with NSIS can help prevent the introduction of similar vulnerabilities in custom installation packages. The vulnerability serves as a reminder of the importance of proper dependency management and explicit linking in software development, particularly for frameworks that handle critical system installation processes. Organizations should also implement monitoring solutions that can detect anomalous behavior during installation processes, as these may indicate exploitation attempts targeting this specific vulnerability.