CVE-2021-31201 in Windows
Summary
by MITRE • 06/09/2021
Microsoft Enhanced Cryptographic Provider Elevation of Privilege Vulnerability
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Analysis
by VulDB Data Team • 10/30/2025
The Microsoft Enhanced Cryptographic Provider Elevation of Privilege Vulnerability represents a critical security flaw within the Windows cryptographic subsystem that allows attackers to escalate their privileges from standard user level to administrative rights. This vulnerability resides in the Enhanced Cryptographic Provider component that handles cryptographic operations and key management within the Windows operating system. The flaw specifically affects systems running Windows 10 and Windows Server 2019, where the cryptographic provider fails to properly validate access controls when processing certain cryptographic operations, creating a pathway for unauthorized privilege escalation.
The technical implementation of this vulnerability stems from insufficient access control validation within the Enhanced Cryptographic Provider module. When legitimate cryptographic operations are performed through this provider, the system does not adequately verify whether the requesting process has proper authorization levels to execute specific cryptographic functions. This weakness enables an attacker with standard user privileges to manipulate cryptographic requests in such a way that the system grants elevated access rights. The vulnerability is particularly concerning because it operates at the kernel level where cryptographic operations are processed, making it difficult to detect through standard user-space monitoring mechanisms.
From an operational perspective, this vulnerability presents significant risks to enterprise environments where attackers could leverage it to gain unauthorized administrative access to critical systems. The exploitation typically involves crafting specific cryptographic requests that bypass normal access control checks, allowing privilege escalation without requiring additional attack vectors. Security researchers have noted that the vulnerability can be exploited through various attack vectors including malicious software installation, web-based attacks, or even physical access scenarios. The impact extends beyond individual system compromise as successful exploitation can lead to complete domain compromise, data exfiltration, and persistence mechanisms within the affected environment.
Organizations should implement immediate mitigations including applying the relevant Microsoft security patches released in the June 2021 security updates, which address the access control validation issues within the Enhanced Cryptographic Provider. Network segmentation and privilege minimization should be enforced to limit potential attack surface, while monitoring systems should be configured to detect anomalous cryptographic operations that might indicate exploitation attempts. The vulnerability aligns with CWE-284 Access Control Issues, specifically addressing improper access control in cryptographic operations, and maps to ATT&CK technique T1068 Privilege Escalation through the use of system vulnerabilities to gain elevated privileges. Additional defensive measures include implementing application control policies to restrict access to cryptographic providers, enabling Windows Defender Application Control, and conducting regular security assessments to identify potential exploitation attempts. Organizations should also consider deploying endpoint detection and response solutions that can monitor for suspicious cryptographic activities and alert on potential privilege escalation attempts.