CVE-2018-8216 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-2018-8217, CVE-2018-8221.
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Analysis
by VulDB Data Team • 08/16/2024
The CVE-2018-8216 vulnerability represents a critical security feature bypass in Microsoft's Device Guard implementation, a Windows security technology designed to enforce code integrity policies and prevent unauthorized code execution. This vulnerability specifically targets the code integrity policy enforcement mechanisms that Device Guard employs to protect against malicious code injection attempts. The flaw allows attackers to circumvent the intended security controls that should prevent arbitrary code execution within PowerShell sessions, effectively undermining the foundational security posture that organizations rely upon for endpoint protection. Device Guard operates under the principle of whitelisting approved code and blocking unauthorized executables, making this bypass particularly concerning for enterprise environments where PowerShell is extensively used for administrative tasks and automation.
The technical exploitation of this vulnerability occurs through a specific flaw in how Device Guard validates code integrity policies during PowerShell session initialization. Attackers can manipulate the policy enforcement mechanisms to inject malicious code that would normally be blocked by Device Guard's code integrity checks. This bypass typically involves crafting specific PowerShell commands or scripts that exploit timing windows or policy validation loopholes within the Device Guard implementation. The vulnerability specifically affects Windows Server 2016 and Windows 10 systems where Device Guard is enabled, making it particularly dangerous in enterprise environments where these operating systems are prevalent. According to CWE classification, this represents a weakness in the security feature bypass category, specifically CWE-1174, which deals with improper enforcement of security policies and controls.
The operational impact of CVE-2018-8216 extends beyond simple code injection capabilities, as it provides attackers with a pathway to establish persistent access and execute arbitrary commands within compromised systems. Once an attacker successfully bypasses Device Guard, they can leverage PowerShell's extensive capabilities to perform reconnaissance, escalate privileges, and deploy additional malicious payloads. The vulnerability's implications are particularly severe because PowerShell is commonly used for legitimate administrative tasks, making malicious PowerShell activity harder to distinguish from normal system behavior. This characteristic aligns with ATT&CK framework technique T1086, which describes PowerShell usage for execution, and T1059, which covers command and scripting interpreter usage. Organizations may experience significant operational disruption as attackers can now bypass security controls that were specifically designed to prevent such activities.
Mitigation strategies for CVE-2018-8216 primarily involve applying Microsoft security updates and patches released in August 2018 as part of the Windows security bulletin. System administrators should prioritize patch deployment across all affected Windows Server 2016 and Windows 10 systems, particularly those with Device Guard enabled. Additionally, organizations should implement enhanced monitoring for suspicious PowerShell activities and consider disabling unnecessary PowerShell functionality where possible. The vulnerability highlights the importance of maintaining up-to-date security controls and demonstrates the necessity of layered defense strategies. Organizations should also review their Device Guard policies to ensure proper enforcement and consider implementing additional security measures such as AppLocker configurations or third-party endpoint protection solutions. Security teams should monitor for indicators of compromise related to PowerShell-based attacks and maintain detailed logging of PowerShell execution activities to detect potential exploitation attempts.