CVE-2018-6661 in True Key
Summary
by MITRE
DLL Side-Loading vulnerability in Microsoft Windows Client in McAfee True Key before 4.20.110 allows local users to gain privilege elevation via not verifying a particular DLL file signature.
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Analysis
by VulDB Data Team • 02/08/2021
The CVE-2018-6661 vulnerability represents a critical DLL side-loading flaw in Microsoft Windows Client affecting McAfee True Key versions prior to 4.20.110. This vulnerability exploits a fundamental weakness in the application's dynamic link library loading mechanism, where the software fails to properly validate digital signatures of loaded modules. The flaw resides in the certificate verification process that should occur when loading dependent DLL files, creating an opportunity for malicious actors to inject unauthorized code into the system. This particular vulnerability demonstrates how insufficient input validation and certificate verification can lead to privilege escalation attacks, making it a significant concern for enterprise security environments where McAfee True Key is deployed.
The technical implementation of this vulnerability stems from the improper handling of DLL loading sequences within the McAfee True Key application. When the application attempts to load specific DLL files, it does not adequately verify the digital signatures of these modules before execution. This creates a side-loading attack vector where an attacker can place a malicious DLL with the same name as a legitimate dependency in a location that gets searched before the genuine DLL. The vulnerability operates under the principle of DLL search order hijacking, where the system loads the attacker-controlled DLL instead of the legitimate one, effectively bypassing the signature verification mechanism. According to CWE-427, this represents a classic uncontrolled search path vulnerability that allows attackers to execute arbitrary code with the privileges of the target process.
The operational impact of CVE-2018-6661 extends beyond simple code execution to privilege escalation capabilities that can severely compromise system integrity. Local users who exploit this vulnerability can elevate their privileges to SYSTEM level, providing complete control over the affected system. This privilege escalation occurs because McAfee True Key typically runs with elevated privileges to perform its security functions, and the vulnerability allows an attacker to inject malicious code into this privileged process. The attack requires local access to the system but does not need network connectivity, making it particularly dangerous in environments where physical access is possible. This vulnerability aligns with ATT&CK technique T1068 which describes local privilege escalation through the exploitation of application vulnerabilities, and T1546 which covers registry run keys and startup folder modifications that could be used in conjunction with this flaw.
Mitigation strategies for CVE-2018-6661 primarily focus on updating the affected software to McAfee True Key version 4.20.110 or later, which includes proper signature verification mechanisms. System administrators should implement application whitelisting policies to restrict the execution of unauthorized DLL files, particularly those with names matching legitimate dependencies. The Windows Defender Application Control feature can be configured to enforce code integrity policies that prevent unsigned or improperly signed DLLs from executing. Additionally, implementing the principle of least privilege reduces the potential impact of such vulnerabilities by limiting the privileges of running applications. Network segmentation and monitoring solutions should be employed to detect unusual DLL loading patterns that may indicate exploitation attempts. Security teams should also consider deploying endpoint detection and response solutions that can identify suspicious side-loading activities and alert on unauthorized DLL injection attempts. The vulnerability highlights the importance of proper code signing practices and the necessity of implementing robust verification mechanisms for all dynamically loaded components in security applications.