CVE-2021-1687 in Windows
Summary
by MITRE • 01/13/2021
Windows WalletService Elevation of Privilege Vulnerability This CVE ID is unique from CVE-2021-1681, CVE-2021-1686, CVE-2021-1690.
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Analysis
by VulDB Data Team • 10/09/2024
The Windows WalletService elevation of privilege vulnerability represents a critical security flaw in Microsoft's Windows operating system that allows attackers to escalate their privileges from standard user level to system level. This vulnerability specifically targets the WalletService component which manages digital wallets and credential storage functionalities within Windows environments. The flaw exists in how the service handles certain authentication and authorization processes, creating an exploitable condition that can be leveraged by malicious actors to gain unauthorized administrative access to affected systems.
Technical exploitation of this vulnerability occurs through improper validation of access tokens and security descriptors within the WalletService implementation. The flaw stems from inadequate input sanitization and insufficient privilege checking mechanisms that allow a local attacker to manipulate service calls and bypass expected security controls. According to CWE classification, this vulnerability maps to CWE-284 which describes improper access control scenarios, specifically involving inadequate privilege management within system services. The vulnerability is particularly concerning because it operates at the service level where Windows components interact with the kernel, creating a direct pathway for privilege escalation attacks that can be executed without requiring physical access to the target system.
The operational impact of CVE-2021-1687 extends beyond simple privilege escalation as it provides attackers with the foundation for more sophisticated attacks within compromised environments. Once elevated to system level, attackers can manipulate system files, install persistent backdoors, access encrypted data, and potentially move laterally across network segments. This vulnerability aligns with ATT&CK technique T1068 which describes the use of elevated privileges to gain system access, and T1547 which covers the abuse of system services for privilege escalation. Organizations running affected Windows versions face significant risk as this vulnerability can be exploited through various attack vectors including malicious software installation, drive-by downloads, or compromised legitimate applications that interact with the WalletService.
Mitigation strategies for this vulnerability require immediate patch deployment through Microsoft's regular security updates, specifically targeting the Windows 10 and Windows 11 operating systems that contain the affected WalletService implementation. System administrators should implement the principle of least privilege by restricting user access to system services and monitoring for unusual WalletService activity. Network segmentation and endpoint detection systems can help identify exploitation attempts by monitoring for suspicious service interactions and privilege escalation patterns. Additionally, organizations should conduct thorough vulnerability assessments to identify systems running vulnerable versions of Windows and prioritize patching efforts accordingly. The vulnerability demonstrates the critical importance of maintaining up-to-date security patches and implementing comprehensive security monitoring solutions to detect and respond to privilege escalation attempts before they can be fully leveraged by threat actors.