CVE-2016-4560 in Tivoli Storage Manager Server
Summary
by MITRE
Untrusted search path vulnerability in Flexera InstallAnywhere 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 • 03/14/2019
The vulnerability identified as CVE-2016-4560 represents a critical untrusted search path issue within Flexera InstallAnywhere software that enables local attackers to escalate privileges through malicious DLL injection techniques. This flaw exists in the setup-launcher executable file where the application fails to properly validate the security context of dynamically loaded libraries, creating an exploitable condition that can be leveraged by adversaries with local system access. The vulnerability stems from the application's insecure handling of dynamic library loading mechanisms, where it searches for required DLL files in the current working directory before examining system directories, thereby allowing attackers to place malicious payloads in locations where legitimate applications expect to find trusted components.
From a technical perspective this vulnerability aligns with CWE-427 Uncontrolled Search Path Element, which specifically addresses the issue of applications searching for libraries or executables in insecure locations that can be manipulated by attackers. The flaw operates by exploiting the Windows dynamic linking process where applications load DLLs based on a predefined search order that prioritizes the current working directory over system directories. When a setup-launcher executable runs in a directory controlled by an attacker, and that directory contains a malicious DLL with the same name as a legitimate system DLL, the application will load the malicious component instead of the intended trusted library, enabling code execution with the privileges of the running process. This behavior violates fundamental security principles of least privilege and proper library resolution mechanisms.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass potential system compromise and persistent access within targeted environments. Local attackers who can influence the current working directory of setup-launcher processes can effectively hijack the execution flow of legitimate installation programs, potentially gaining administrative privileges or executing arbitrary code within the context of the vulnerable application. This vulnerability is particularly concerning in enterprise environments where installation tools are frequently used and may run with elevated privileges, as it can be exploited to establish persistent backdoors or escalate privileges to system-level access. The attack vector is relatively straightforward requiring only local system access and the ability to place files in targeted directories, making it an attractive target for both insider threats and external attackers who have already gained initial access to a system.
Mitigation strategies for CVE-2016-4560 should focus on addressing the root cause through proper application hardening and secure coding practices that align with industry standards such as those recommended in the MITRE ATT&CK framework under techniques related to privilege escalation and persistence. Organizations should implement strict directory permissions and ensure that setup-launcher executables are run from secure, isolated directories that cannot be manipulated by local users. The recommended approach includes updating to patched versions of Flexera InstallAnywhere where the vulnerable search path behavior has been corrected, implementing application whitelisting policies to restrict which executables can run in privileged contexts, and employing secure coding practices that explicitly define library search paths using absolute paths rather than relying on relative directory searches. Additionally, system administrators should conduct regular audits of installation directories and implement monitoring for suspicious DLL loading activities that could indicate exploitation attempts, ensuring that security controls are in place to prevent the exploitation of similar vulnerabilities in other software components.