CVE-2017-10836 in Optimal Guard
Summary
by MITRE
Untrusted search path vulnerability in Optimal Guard 1.1.21 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 • 11/11/2019
The vulnerability identified as CVE-2017-10836 represents a critical untrusted search path issue affecting Optimal Guard versions 1.1.21 and earlier. This flaw resides in the software's dynamic link library loading mechanism, where the application fails to properly validate or restrict the directories from which it loads executable components. The vulnerability stems from the application's improper handling of the Windows dynamic link library search order, allowing an attacker to place a malicious DLL in a directory that the application will search before the legitimate system directories. This weakness specifically impacts the privilege escalation capabilities of malicious actors who can leverage the Trojan horse DLL technique to execute arbitrary code with elevated privileges. The vulnerability aligns with CWE-427 Uncontrolled Search Path Element, which describes how applications that search for files in untrusted directories without proper validation can be exploited. The flaw exists because the software does not implement proper DLL search path security measures, such as using the LoadLibraryEx function with the LOAD_WITH_ALTERED_SEARCH_PATH flag or implementing explicit path validation.
The technical exploitation of this vulnerability occurs when an attacker places a malicious DLL with the same name as a legitimate library that the Optimal Guard application expects to load. When the application executes and attempts to load the expected library, it inadvertently loads the attacker-controlled DLL from a directory that appears earlier in the search path. This behavior enables privilege escalation attacks where the malicious code runs with the privileges of the compromised application, potentially allowing attackers to execute commands, modify system files, or establish persistent access. The vulnerability is particularly dangerous because it can be exploited without requiring user interaction or elevated privileges initially, as the application itself performs the loading operation. The attack vector is consistent with techniques described in the MITRE ATT&CK framework under T1059 Command and Scripting Interpreter and T1068 Exploitation for Privilege Escalation. The search path vulnerability creates a persistent threat because the malicious DLL remains in the compromised directory even after the initial attack, allowing for continued exploitation.
The operational impact of CVE-2017-10836 extends beyond simple privilege escalation to encompass potential system compromise and data exfiltration capabilities. Organizations running affected versions of Optimal Guard face significant risk of unauthorized access to sensitive systems, particularly in environments where the software is installed with administrative privileges or operates in security-critical contexts. The vulnerability affects the integrity and confidentiality of systems because the malicious DLL can intercept or manipulate communications, modify system configurations, or provide backdoor access to attackers. Security professionals must consider that this vulnerability could be combined with other attack vectors to create more sophisticated exploitation chains, potentially leading to complete system compromise. The impact is amplified in enterprise environments where multiple systems may be running vulnerable versions of the software, creating a potential attack surface that could be leveraged for lateral movement within networks. Organizations should implement immediate mitigations including patching to the latest versions of Optimal Guard, implementing proper application whitelisting policies, and conducting thorough security assessments to identify any potential exploitation attempts. The vulnerability demonstrates the critical importance of proper DLL search path handling in security-sensitive applications and serves as a reminder of the need for robust application security practices in software development lifecycle processes.