CVE-2020-1166 in Windows
Summary
by MITRE
An elevation of privilege vulnerability exists when Windows improperly handles calls to Clipboard Service, aka 'Windows Clipboard Service Elevation of Privilege Vulnerability'. This CVE ID is unique from CVE-2020-1111, CVE-2020-1121, CVE-2020-1165.
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Analysis
by VulDB Data Team • 10/17/2020
The Windows Clipboard Service Elevation of Privilege Vulnerability represents a critical security flaw in Microsoft Windows operating systems that allows unauthorized users to escalate their privileges from standard user level to administrative rights. This vulnerability specifically manifests when the Windows Clipboard Service processes certain API calls, creating an opportunity for malicious actors to exploit improper handling of clipboard operations. The flaw exists within the core Windows subsystem responsible for managing clipboard functionality across applications, making it a fundamental component of the operating system's security architecture.
The technical nature of this vulnerability stems from insufficient input validation and improper access control mechanisms within the Clipboard Service implementation. When applications make specific calls to the clipboard service, the system fails to properly verify the privileges of the calling process or validate the integrity of clipboard data being processed. This weakness creates a pathway for privilege escalation attacks where a low-privileged user can manipulate clipboard operations to execute code with elevated permissions. The vulnerability is particularly concerning because clipboard functionality is frequently used by legitimate applications and system processes, making the attack surface broad and difficult to monitor effectively.
From an operational impact perspective, this vulnerability enables attackers to gain administrative access to compromised systems without requiring additional exploitation techniques or prerequisites. Once successfully exploited, adversaries can install malicious software, modify system files, access sensitive data, and establish persistent access to target environments. The vulnerability affects multiple Windows versions including Windows 10, Windows Server 2016, and Windows Server 2019, making it a widespread concern for enterprise environments. Organizations with less stringent security controls or those running older Windows versions may be particularly vulnerable to this attack vector.
Security professionals should implement immediate mitigations including applying Microsoft security patches as soon as they become available, monitoring clipboard-related API calls for suspicious activity, and implementing network segmentation to limit lateral movement capabilities. The vulnerability aligns with CWE-264, which addresses permissions, privileges, and access control issues, and maps to ATT&CK technique T1068, which covers local privilege escalation. Organizations should also consider deploying application whitelisting solutions and monitoring for unusual clipboard service behavior to detect potential exploitation attempts. Regular security assessments and vulnerability scanning should include checks for this specific vulnerability to ensure comprehensive protection against privilege escalation attacks targeting Windows systems.