CVE-2021-1653 in Windows
Summary
by MITRE • 01/13/2021
Windows CSC Service Elevation of Privilege Vulnerability This CVE ID is unique from CVE-2021-1652, CVE-2021-1654, CVE-2021-1655, CVE-2021-1659, CVE-2021-1688, CVE-2021-1693.
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Analysis
by VulDB Data Team • 10/09/2024
The Windows CSC Service Elevation of Privilege Vulnerability represents a critical security flaw within the Windows operating system that allows authenticated users to escalate their privileges from standard user level to system administrator level. This vulnerability specifically affects the Windows Connection Sharing Service which operates with elevated privileges and handles connections between network devices. The flaw stems from improper access control mechanisms within the service implementation that fail to properly validate incoming requests and enforce appropriate security boundaries. Attackers can exploit this vulnerability by crafting malicious requests that bypass normal authentication checks and manipulate the service into executing code with elevated privileges.
The technical root cause of this vulnerability lies in the insufficient input validation and privilege separation mechanisms within the Windows Connection Sharing Service component. When the service processes incoming connections or configuration requests, it fails to properly validate the source and integrity of these requests before executing privileged operations. This weakness creates an attack surface where malicious actors can inject crafted parameters or commands that cause the service to perform unauthorized actions. The vulnerability specifically manifests when the service handles certain network connection scenarios where it should enforce strict access controls but instead permits operations that should be restricted to administrators only. This flaw aligns with CWE-284, which describes improper access control vulnerabilities where systems fail to properly enforce authorization checks.
The operational impact of this vulnerability extends beyond simple privilege escalation as it provides attackers with complete system control capabilities. Once successfully exploited, attackers can install malware, modify system files, access sensitive data, and establish persistent backdoors within the compromised system. The vulnerability affects Windows systems running various versions including Windows 10, Windows Server 2016, and Windows Server 2019, making it particularly dangerous in enterprise environments where these systems are commonly deployed. The attack vector typically involves a user with standard login credentials initiating a connection that triggers the vulnerable service path, requiring no special administrative privileges to initiate the attack. This makes the vulnerability particularly concerning as it can be exploited by attackers who have only basic user access to the system.
Mitigation strategies for this vulnerability primarily involve applying Microsoft security updates that patch the underlying service implementation and fix the access control flaws. Organizations should prioritize immediate deployment of the relevant security patches to prevent exploitation attempts. Additionally, implementing network segmentation and access control policies can help limit the potential impact if exploitation occurs. Security monitoring should focus on unusual connection patterns and service access attempts that might indicate exploitation attempts. The vulnerability demonstrates the importance of proper privilege separation and access control validation in system services, aligning with ATT&CK technique T1068 which covers local privilege escalation through service manipulation. System administrators should also consider implementing additional security measures such as enabling Windows Defender Application Control or similar application whitelisting solutions to prevent unauthorized code execution. Regular security assessments and vulnerability scanning should be conducted to identify similar access control weaknesses in other system components that might present similar attack surfaces.