CVE-2023-35340 in Windows
Summary
by MITRE • 07/11/2023
Windows CNG Key Isolation Service Elevation of Privilege Vulnerability
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Analysis
by VulDB Data Team • 06/13/2026
This vulnerability resides in the Windows Cryptography Next Generation Key Isolation Service which is responsible for managing cryptographic keys and ensuring their secure isolation within the operating system. The flaw allows a local attacker to escalate privileges from a standard user account to system level access through improper handling of cryptographic key operations. The vulnerability specifically affects the CNG Key Isolation Service component that manages key storage and access controls, creating a path for privilege escalation attacks that bypass normal security boundaries. According to the Common Weakness Enumeration framework, this represents a weakness categorized under CWE-264, which deals with permissions, privileges, and access controls, specifically involving improper privilege management during cryptographic operations.
The technical implementation flaw stems from insufficient validation of access controls within the CNG Key Isolation Service when processing cryptographic key operations. Attackers can exploit this by manipulating key access requests and leveraging the service's failure to properly validate user permissions before granting access to protected cryptographic resources. The vulnerability manifests when the service processes certain key operations without adequate verification of the requesting process's security context, allowing unauthorized access to keys that should be restricted to system-level operations. This misconfiguration creates a path where a low-privilege user process can gain elevated privileges by exploiting the service's insufficient access control mechanisms during key management operations.
The operational impact of this vulnerability is significant as it provides attackers with a direct path to system compromise without requiring external exploitation vectors or complex attack chains. Once exploited, the privilege escalation allows attackers to gain full control over the affected system, enabling them to install malware, modify system files, access sensitive data, or establish persistence mechanisms. The vulnerability affects all versions of Windows that implement the CNG Key Isolation Service, making it particularly dangerous in enterprise environments where multiple systems may be vulnerable. From an ATT&CK framework perspective, this vulnerability maps to privilege escalation techniques under T1068, where adversaries leverage system-level access to execute malicious code with elevated privileges.
Mitigation strategies should focus on immediate patch application through Microsoft's security updates, which address the underlying access control flaws in the CNG Key Isolation Service. System administrators should also implement additional monitoring of cryptographic service operations and access patterns that may indicate exploitation attempts. Network segmentation and least privilege principles should be enforced to limit potential lateral movement if the vulnerability is successfully exploited. Organizations should also conduct regular security assessments of their cryptographic implementations and ensure proper configuration of access controls within the Windows security model. The vulnerability highlights the importance of proper privilege management in cryptographic services and demonstrates how weaknesses in key isolation mechanisms can lead to system-wide compromise.