CVE-2018-8201 in Windows
Summary
by MITRE
A security feature bypass vulnerability exists in Device Guard that could allow an attacker to inject malicious code into a Windows PowerShell session, aka "Device Guard Code Integrity Policy Security Feature Bypass Vulnerability." This affects Windows Server 2016, Windows 10, Windows 10 Servers. This CVE ID is unique from CVE-2018-8211, CVE-2018-8212, CVE-2018-8215, CVE-2018-8216, CVE-2018-8217, CVE-2018-8221.
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Analysis
by VulDB Data Team • 03/27/2023
The CVE-2018-8201 vulnerability represents a critical security feature bypass in Microsoft's Device Guard implementation, specifically targeting the code integrity policy enforcement mechanisms that are fundamental to Windows security architecture. This vulnerability exists within the Windows operating system's Device Guard feature, which is designed to prevent unauthorized code execution by enforcing strict code integrity policies that control which applications and scripts can run on a system. The flaw allows attackers to circumvent these protective measures, creating a pathway for malicious code injection into Windows PowerShell sessions without proper authorization.
The technical nature of this vulnerability stems from a flaw in how Device Guard validates code integrity policies during PowerShell session initialization. When a PowerShell session is established, Device Guard should enforce strict policy checks that prevent execution of unsigned or unauthorized code. However, the vulnerability allows an attacker to manipulate the policy validation process, effectively disabling or bypassing the code integrity enforcement mechanisms. This occurs through a specific manipulation of the policy evaluation logic that permits malicious code to execute with elevated privileges while appearing to comply with the established security policies.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it fundamentally undermines the security model that Device Guard is designed to enforce. Attackers can leverage this vulnerability to inject malicious PowerShell scripts that can execute with the privileges of the targeted user or system, potentially leading to full system compromise. The vulnerability affects multiple Windows platforms including Windows Server 2016, Windows 10, and Windows 10 Servers, making it particularly dangerous in enterprise environments where these systems are prevalent. The security implications are severe because PowerShell is commonly used for administrative tasks and system management, providing attackers with a powerful vector for persistent access and lateral movement within networks.
This vulnerability aligns with CWE-119, which addresses "Improper Restriction of Operations within the Bounds of a Memory Buffer," and maps to ATT&CK technique T1059.001 for Command and Scripting Interpreter. The bypass mechanism specifically targets the code integrity enforcement controls that are critical for preventing malicious code execution, making it a prime target for attackers seeking to establish persistent footholds in secure environments. Organizations affected by this vulnerability face increased risk of advanced persistent threats, as the bypass allows attackers to execute malicious code that would normally be blocked by Device Guard policies. The vulnerability's impact is compounded by the fact that it operates at a low level within the Windows security stack, making detection and remediation more challenging.
Mitigation strategies for CVE-2018-8201 should prioritize immediate implementation of Microsoft security updates and patches, as these address the core policy validation flaw that enables the bypass. Organizations should also implement additional monitoring for suspicious PowerShell activity and ensure that Device Guard policies are properly configured with strict enforcement settings. Network segmentation and least privilege access controls can help limit the potential damage from successful exploitation, while regular security assessments should verify that code integrity policies remain effective. The vulnerability demonstrates the importance of maintaining up-to-date security controls and highlights the need for continuous monitoring of security features that are critical to Windows system integrity, as bypasses of code integrity mechanisms can have cascading effects on overall system security posture.