CVE-2016-2542 in InstallShield
Summary
by MITRE
Untrusted search path vulnerability in Flexera InstallShield through 2015 SP1 allows local users to gain privileges via a Trojan horse DLL in the current working directory of a setup-launcher executable file.
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Analysis
by VulDB Data Team • 07/08/2022
The vulnerability identified as CVE-2016-2542 represents a critical untrusted search path weakness within Flexera InstallShield software versions up to and including 2015 SP1. This flaw exists in the setup-launcher executable file's handling of dynamic link library loading processes, creating a privilege escalation vector that adversaries can exploit through malicious code injection. The vulnerability specifically affects the manner in which the installer resolves library dependencies when executing setup-launcher programs, allowing attackers to place malicious DLL files in the current working directory where the setup-launcher operates.
The technical implementation of this vulnerability stems from improper handling of dynamic library loading sequences within the InstallShield framework. When a setup-launcher executable runs, it searches for required DLL libraries in a predictable order that includes the current working directory before checking system directories. This search path behavior creates an opportunity for local attackers to place a malicious DLL with the same name as a legitimate library that the setup-launcher expects to load. The flaw aligns with CWE-426, which describes untrusted search path vulnerabilities where applications search for libraries in insecure locations, and also relates to CWE-276, concerning improper privileges and access control mechanisms. The vulnerability operates under the principle that applications should not trust libraries loaded from the current working directory without proper validation and integrity checks.
The operational impact of CVE-2016-2542 extends beyond simple privilege escalation to encompass broader system compromise capabilities. Local users who can manipulate the current working directory of setup-launcher processes gain the ability to execute arbitrary code with elevated privileges, potentially allowing for system takeover, data exfiltration, or persistence establishment. Attackers can leverage this vulnerability to deploy malware or backdoors through legitimate installation processes, making detection more challenging as the malicious activity appears to originate from trusted installer components. The attack vector is particularly concerning because it requires minimal user interaction beyond placing the malicious DLL in the appropriate location, making it suitable for automated exploitation campaigns. This vulnerability also maps to ATT&CK technique T1068, which covers local privilege escalation through the exploitation of system vulnerabilities, and T1059, involving the execution of malicious code through legitimate system processes.
Mitigation strategies for CVE-2016-2542 should focus on both immediate remediation and long-term architectural improvements. The most effective immediate solution involves upgrading to Flexera InstallShield versions that address this specific vulnerability, as the manufacturer has released patches to correct the untrusted search path behavior. Organizations should implement strict file system permissions and access controls to prevent unauthorized users from writing to directories where setup-launcher executables operate. System administrators should also conduct comprehensive audits to identify and remove any instances of vulnerable InstallShield versions from production environments. Additional defensive measures include implementing application whitelisting policies that restrict which DLLs can be loaded by setup-launcher processes, enabling secure library loading mechanisms that prioritize system directories over current working directories, and deploying endpoint protection solutions capable of monitoring for suspicious DLL loading patterns. Network segmentation and privilege separation can further reduce the attack surface by limiting the ability of local users to manipulate installation processes and their associated working directories.