CVE-2018-8217 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. This CVE ID is unique from CVE-2018-8201, CVE-2018-8211, CVE-2018-8212, CVE-2018-8215, CVE-2018-8216, CVE-2018-8221.
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Analysis
by VulDB Data Team • 08/16/2024
The CVE-2018-8217 vulnerability represents a critical security feature bypass in Windows Device Guard technology that fundamentally undermines code integrity protections designed to prevent unauthorized code execution. This vulnerability specifically targets the code integrity policy enforcement mechanisms within Device Guard, which is a Windows security feature that restricts the execution of scripts and applications based on predefined policies. The flaw allows attackers to circumvent these protective measures and inject malicious PowerShell code into legitimate sessions, creating a persistent threat vector that can be exploited across multiple Windows versions including Windows 10 and Windows Server 2016. The vulnerability's classification as a security feature bypass aligns with CWE-119, which addresses weaknesses in memory handling that can lead to privilege escalation and code injection attacks. This issue represents a significant deviation from the intended security posture of Device Guard, which is designed to enforce strict code integrity policies and prevent the execution of unsigned or unauthorized code.
The technical exploitation of CVE-2018-8217 occurs through a specific flaw in how Device Guard validates code integrity policies during PowerShell session initialization. Attackers can leverage this bypass to inject malicious PowerShell commands that execute with the privileges of the targeted user or system, depending on the execution context. The vulnerability exploits a gap in the policy enforcement mechanism that should have prevented code execution from unauthorized sources, allowing threat actors to execute arbitrary PowerShell commands without triggering the security features that Device Guard is designed to provide. This flaw specifically affects the Windows PowerShell execution policy enforcement, which is a core component of the Windows security architecture that controls script execution based on various policy parameters. The vulnerability's impact is particularly severe because PowerShell is extensively used in enterprise environments for administrative tasks and script execution, making it a prime target for attackers seeking to establish persistent access and escalate privileges within compromised systems.
The operational impact of CVE-2018-8217 extends beyond simple code injection capabilities and represents a fundamental compromise of Windows security controls that organizations rely upon for protection against malicious code execution. This vulnerability enables attackers to bypass the code integrity policies that are essential for preventing the execution of malicious PowerShell scripts, which are commonly used in advanced persistent threat campaigns and lateral movement operations. The attack surface is particularly concerning because it affects both Windows 10 client operating systems and Windows Server 2016 server environments, providing attackers with multiple entry points and execution contexts. Organizations that have implemented Device Guard as part of their security strategy may find their protections effectively nullified, leaving systems vulnerable to sophisticated attacks that leverage PowerShell-based exploitation techniques. The vulnerability's relationship to the ATT&CK framework is particularly relevant as it maps to techniques involving 'PowerShell' and 'Code Injection' which are commonly used in enterprise security breaches, with this specific vulnerability enabling adversaries to circumvent built-in protections designed to prevent such activities.
Mitigation strategies for CVE-2018-8217 require immediate attention and should include applying the relevant Microsoft security updates that address the Device Guard policy bypass vulnerability. Organizations should also implement additional monitoring and detection measures focused on PowerShell execution patterns and unusual code injection activities. The vulnerability highlights the importance of maintaining current security patches and implementing layered defense strategies that do not rely solely on a single security control mechanism. Network segmentation and principle of least privilege configurations can help limit the potential impact of successful exploitation attempts, while enhanced logging and monitoring of PowerShell activities can aid in detecting unauthorized code injection attempts. Security teams should also consider implementing additional controls such as AppLocker or other application control mechanisms to provide alternative protection layers that can function even when Device Guard protections are compromised. The vulnerability's unique nature as a security feature bypass rather than a traditional exploit means that organizations must ensure comprehensive patch management processes are in place to address similar issues that may arise in the future, as the underlying principle of bypassing code integrity controls represents a fundamental threat to Windows security architecture.