CVE-2017-0218 in Windows
Summary
by MITRE
Microsoft Windows 10 Gold, Windows 10 1511, Windows 10 1607, and Windows Server 2016 allow an attacker to exploit a security feature bypass vulnerability in Device Guard that could allow the attacker to inject malicious code into a Windows PowerShell session, aka "Device Guard Code Integrity Policy Security Feature Bypass Vulnerability." This CVE ID is unique from CVE-2017-0173, CVE-2017-0215, CVE-2017-0216, and CVE-2017-0219.
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Analysis
by VulDB Data Team • 12/27/2020
The vulnerability identified as CVE-2017-0218 represents a critical security feature bypass in Microsoft Windows operating systems including Windows 10 Gold, Windows 10 version 1511, Windows 10 version 1607, and Windows Server 2016. This flaw specifically targets Device Guard functionality, which serves as a code integrity protection mechanism designed to prevent the execution of unauthorized code by enforcing strict policies that govern which applications and scripts can run on a system. The vulnerability arises from a weakness in how Device Guard validates code integrity policies, creating an avenue for attackers to circumvent these protective measures. The flaw enables malicious actors to inject harmful code into Windows PowerShell sessions, effectively undermining the security controls that Device Guard is intended to provide.
The technical implementation of this vulnerability stems from insufficient validation mechanisms within Device Guard's code integrity policy enforcement. When PowerShell sessions execute, the system should verify that all code adheres to established security policies before allowing execution. However, the flaw allows attackers to manipulate the policy validation process, enabling them to bypass these checks and execute arbitrary code within the PowerShell environment. This bypass occurs at the policy enforcement layer where Device Guard should be strictly enforcing code integrity requirements but fails to properly validate the integrity of code being executed. The vulnerability specifically affects PowerShell sessions where the attacker can leverage the bypass to inject malicious scripts or binaries that would otherwise be blocked by Device Guard's policy enforcement mechanisms.
The operational impact of CVE-2017-0218 extends beyond simple code injection capabilities, as it represents a significant compromise to endpoint security posture. Attackers can leverage this vulnerability to establish persistent access to systems by injecting malicious PowerShell scripts that can execute commands, exfiltrate data, or deploy additional malware payloads. The vulnerability is particularly dangerous because it operates at a system-level security control, meaning that successful exploitation can lead to complete system compromise without requiring additional privilege escalation. Organizations using Windows 10 and Windows Server 2016 with Device Guard enabled face elevated risk of advanced persistent threats and lateral movement attacks, as the vulnerability allows attackers to bypass the very controls designed to prevent such activities. This makes the vulnerability particularly attractive to threat actors conducting targeted attacks against enterprise environments where Device Guard is deployed as part of security defense strategies.
Mitigation strategies for CVE-2017-0218 should focus on immediate patch application from Microsoft, as the vulnerability requires a software update to address the underlying Device Guard policy validation flaw. Organizations should also implement additional monitoring measures to detect suspicious PowerShell activity, particularly around code injection attempts and unusual script execution patterns. Network segmentation and privilege separation can help limit the potential impact of successful exploitation, while enhanced logging and audit capabilities should be enabled to detect unauthorized code execution attempts. Security teams should also consider implementing additional PowerShell security controls beyond Device Guard, such as PowerShell script block logging and constrained language mode enforcement. The vulnerability aligns with ATT&CK technique T1059.001 for PowerShell execution and T1068 for exploit for privilege escalation, making it particularly relevant for organizations implementing defensive security measures aligned with MITRE ATT&CK framework guidelines. This vulnerability falls under CWE-284, which addresses improper access control, and represents a critical failure in the code integrity enforcement mechanisms that should prevent unauthorized code execution.