CVE-2016-3958 in Google
Summary
by MITRE
Untrusted search path vulnerability in Go before 1.5.4 and 1.6.x before 1.6.1 on Windows allows local users to gain privileges via a Trojan horse DLL in the current working directory, related to use of the LoadLibrary function.
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Analysis
by VulDB Data Team • 10/06/2024
The vulnerability identified as CVE-2016-3958 represents a critical untrusted search path issue affecting the Go programming language runtime on Windows systems. This flaw exists in Go versions prior to 1.5.4 and 1.6.x versions before 1.6.1, creating a significant security risk for applications running on Windows platforms. The vulnerability stems from how the Go runtime handles dynamic library loading on Windows operating systems, specifically through the improper use of the LoadLibrary function which does not properly validate the source of loaded libraries.
The technical implementation of this vulnerability exploits the Windows dynamic link library loading mechanism where the system searches for required DLLs in a specific order including the current working directory. When a Go application running on Windows loads dynamic libraries, it uses LoadLibrary which follows the standard Windows DLL search order that includes the current working directory before checking system directories. This behavior creates an opportunity for privilege escalation attacks where a malicious actor can place a specially crafted Trojan horse DLL in the application's working directory, causing the application to load and execute the malicious code with the privileges of the user running the application.
This vulnerability directly maps to CWE-427 Uncontrolled Search Path Element, which describes situations where applications use search paths that include untrusted directories, allowing attackers to place malicious files in those locations. The flaw also aligns with ATT&CK technique T1068, which covers the exploitation of legitimate system tools and libraries to gain unauthorized access or execute malicious code. The operational impact of this vulnerability is severe as it allows local users to escalate privileges without requiring administrative rights, potentially enabling attackers to execute arbitrary code with elevated permissions.
The privilege escalation capability arises because when an application loads a malicious DLL from the current working directory, the loaded code executes with the same privileges as the parent process. If the application runs with elevated privileges, the malicious code will also execute with those privileges, potentially allowing attackers to gain system-level access. This vulnerability particularly affects Go applications that dynamically load libraries on Windows systems, making it a widespread concern across applications built with this programming language on Windows platforms.
Mitigation strategies for CVE-2016-3958 include upgrading to Go versions 1.5.4 or later, or 1.6.1 and later, which contain fixes addressing the untrusted search path behavior. Additionally, system administrators should implement proper directory permissions and ensure that application working directories have restricted write access. The recommended approach involves configuring applications to use absolute paths for library loading and implementing proper DLL search path controls. Organizations should also consider deploying application whitelisting solutions that prevent execution of unauthorized DLLs, and conduct regular security assessments to identify applications vulnerable to this type of attack vector. The fix implemented in Go versions 1.5.4 and 1.6.1 involved modifying the library loading behavior to use more secure search paths that prioritize system directories over the current working directory.