CVE-2020-0785 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 • 04/10/2024
The Windows User Profile Service Elevation of Privilege Vulnerability represents a critical security flaw in Microsoft Windows operating systems that allows local attackers to escalate their privileges from standard user level to system level. This vulnerability specifically affects the ProfSvc component responsible for managing user profiles and personalization settings within the Windows environment. The issue stems from improper handling of symbolic links within the user profile service framework, creating a path traversal condition that can be exploited to gain unauthorized system-level access.
The technical root cause of this vulnerability lies in the Windows User Profile Service's insufficient validation of symbolic link references during profile processing operations. When the service encounters a symbolic link pointing to a restricted system location, it fails to properly verify the target path or validate the link's integrity before attempting to access or modify the referenced resources. This flaw enables an attacker to create malicious symbolic links that point to system-critical files or directories, allowing them to manipulate or overwrite protected components. The vulnerability manifests when the service processes user profiles containing these crafted symbolic links, leading to privilege escalation through improper access control enforcement.
The operational impact of CVE-2020-0785 is severe and far-reaching across enterprise environments, particularly affecting Windows 10 versions and Windows Server 2019 systems. Attackers exploiting this vulnerability can execute arbitrary code with SYSTEM privileges, potentially leading to complete system compromise, data exfiltration, and persistent backdoor establishment. The vulnerability is particularly dangerous because it requires no special privileges to exploit, making it accessible to any local user who can create symbolic links within their user profile directory. This characteristic aligns with attack patterns documented in the MITRE ATT&CK framework under privilege escalation techniques, specifically targeting service manipulation and file system permissions.
Security researchers have classified this vulnerability as a path traversal issue with elevated privilege implications, mapping directly to CWE-22 (Improper Limitation of a Pathname to a Restricted Directory) and CWE-78 (Improper Neutralization of Special Elements used in OS Command). The exploitability of this flaw is enhanced by the fact that it operates within a legitimate Windows service process, making detection more challenging for traditional security monitoring systems. Organizations running affected Windows versions face significant risk of unauthorized access and system compromise, particularly in environments where local user accounts are prevalent. The vulnerability's presence in core Windows services makes it particularly attractive to advanced persistent threat actors seeking long-term system access and control.
Mitigation strategies for CVE-2020-0785 primarily focus on applying Microsoft's security patches and updates released through the Windows Update mechanism. Organizations should prioritize immediate deployment of the relevant security updates to remediate the vulnerability. Additionally, implementing strict file system permissions and access controls can help limit the impact of potential exploitation attempts. Security administrators should monitor for unusual symbolic link creation activities within user profile directories and consider implementing application whitelisting policies to prevent unauthorized executable modifications. Network segmentation and privilege least-privilege principles can further reduce the attack surface and limit potential damage from successful exploitation attempts.