CVE-2020-0730 in Windows
Summary
by MITRE
An elevation of privilege vulnerability exists when the Windows User Profile Service (ProfSvc) improperly handles symlinks, aka 'Windows User Profile Service Elevation of Privilege Vulnerability'.
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Analysis
by VulDB Data Team • 03/30/2024
The Windows User Profile Service Elevation of Privilege Vulnerability represents a critical security flaw in Microsoft Windows operating systems that allows attackers to escalate their privileges from standard user level to system level through improper symlink handling. This vulnerability specifically affects the ProfSvc component responsible for managing user profiles and their associated settings within the Windows environment. The issue stems from the service's inadequate validation of symbolic link references when processing user profile data, creating a pathway for malicious actors to manipulate the system's file access controls and gain unauthorized administrative privileges.
The technical exploitation of this vulnerability occurs when the User Profile Service processes user profile directories containing malicious symbolic links. When the service attempts to resolve these symlinks for profile management operations, it fails to properly validate the target paths, allowing attackers to redirect file operations to arbitrary locations on the system. This flaw falls under the Common Weakness Enumeration category of improper validation of symlink targets, specifically CWE-59, which deals with improper handling of symbolic links. The vulnerability exists because the service does not adequately verify that symbolic links point to legitimate locations within the expected profile hierarchy, enabling attackers to create malicious symlinks that redirect operations to protected system directories.
From an operational impact perspective, this vulnerability poses significant risk to enterprise environments where multiple users interact with Windows systems. Attackers can leverage this flaw to execute arbitrary code with system-level privileges, potentially leading to complete system compromise, data exfiltration, or persistent backdoor installation. The vulnerability affects Windows 10 versions 1903 and 1909, as well as Windows Server 2019 and Windows Server 2016, making it particularly concerning for organizations running these operating systems. The attack vector typically involves an attacker first gaining access to a standard user account, then using the symlink manipulation technique to escalate privileges without requiring additional authentication or specialized tools. This makes the vulnerability particularly dangerous as it can be exploited by threat actors with minimal initial access.
Mitigation strategies for this vulnerability include immediate deployment of Microsoft security patches, which address the improper symlink handling in the ProfSvc component. Organizations should also implement strict access controls and monitoring of user profile directories to detect potential symlink manipulation attempts. The mitigation approach aligns with ATT&CK technique T1068, which covers the use of privilege escalation techniques, and specifically addresses the exploitation of Windows service vulnerabilities. Additional protective measures include restricting user permissions on system directories, implementing application whitelisting policies, and conducting regular security audits of user profile management configurations. Network segmentation and monitoring solutions should be deployed to detect anomalous file access patterns that may indicate symlink-based privilege escalation attempts, particularly focusing on the User Profile Service's interaction with user profile directories.