CVE-2016-0188 in Internet Explorer
Summary
by MITRE
The User Mode Code Integrity (UMCI) implementation in Device Guard in Microsoft Internet Explorer 11 allows remote attackers to bypass a code-signing protection mechanism via unspecified vectors, aka "Internet Explorer Security Feature Bypass."
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Analysis
by VulDB Data Team • 08/18/2022
The vulnerability identified as CVE-2016-0188 resides within the User Mode Code Integrity implementation of Device Guard functionality in Microsoft Internet Explorer 11, representing a critical security flaw that undermines the code-signing protection mechanisms designed to prevent unauthorized code execution. This issue specifically affects the browser's ability to enforce digital signatures on executable code, creating a pathway for malicious actors to circumvent security controls that should otherwise prevent the execution of unsigned or improperly signed software components. The vulnerability operates at the intersection of operating system security policies and browser execution environments, where the Device Guard feature is intended to provide an additional layer of protection by enforcing strict code integrity checks before allowing execution of potentially malicious code.
The technical implementation flaw involves the UMCI subsystem within Internet Explorer 11 that fails to properly validate code-signing certificates or enforce the security policies established by Device Guard when processing web content. Attackers can exploit this weakness through unspecified vectors that likely involve manipulating the browser's code execution flow or leveraging specific combinations of script execution contexts that bypass the normal certificate validation procedures. This bypass mechanism allows adversaries to execute malicious code without proper digital signatures, effectively neutralizing the intended security controls that should prevent the execution of unsigned binaries or scripts that might otherwise be flagged as potentially malicious. The vulnerability demonstrates a failure in the integrity checking mechanisms that should maintain the security boundaries between trusted and untrusted code execution environments.
The operational impact of CVE-2016-0188 extends beyond simple code execution bypass, as it represents a fundamental weakness in Microsoft's security architecture that could enable more sophisticated attacks. Once an attacker successfully exploits this vulnerability, they can potentially execute arbitrary code with the privileges of the user running Internet Explorer, leading to full system compromise. The security implications are particularly severe because Device Guard is designed to prevent the execution of unsigned code, which is a core defense mechanism against zero-day exploits and advanced persistent threats. This vulnerability essentially creates a backdoor that allows attackers to circumvent the very protections that should prevent code injection attacks, privilege escalation, and other malicious activities that rely on executing unsigned or improperly signed code.
Mitigation strategies for this vulnerability require immediate implementation of Microsoft security updates and patches that address the specific UMCI implementation flaw within Device Guard functionality. Organizations should also consider implementing additional security controls such as enhanced browser hardening measures, network-level protections, and monitoring for suspicious code execution patterns that might indicate exploitation attempts. The vulnerability aligns with attack patterns documented in the ATT&CK framework under techniques related to privilege escalation and code injection, where adversaries leverage security feature bypasses to gain elevated privileges. From a compliance perspective, this vulnerability violates security standards such as those outlined in CWE-254, which addresses weaknesses in security features, and represents a significant concern for organizations required to maintain strict security controls. Security teams should also implement behavioral monitoring solutions that can detect anomalous code execution patterns consistent with this type of security feature bypass, as traditional signature-based detection may not be sufficient to identify exploitation attempts.